feat(hub): add SQLAlchemy 2.0 async DB layer + Alembic

Models: User, Node, Group, GroupMember, GEKBundle, RefreshToken, IPLog.
Engine configurable via MESHBAY_DATABASE_URL (asyncpg/aiosqlite).
Alembic async env.py + initial_schema migration autogenerated.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

8 files changed, 624 insertions, 0 deletions

diff --git a/packages/meshbay-hub/alembic.ini b/packages/meshbay-hub/alembic.ini
new file mode 100644
index 0000000..fe45eb2
--- /dev/null
+++ b/packages/meshbay-hub/alembic.ini
@@ -0,0 +1,149 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts.
+# this is typically a path given in POSIX (e.g. forward slashes)
+# format, relative to the token %(here)s which refers to the location of this
+# ini file
+script_location = %(here)s/src/meshbay_hub/db/migrations
+
+# template used to generate migration file names; The default value is %%(rev)s_%%(slug)s
+# Uncomment the line below if you want the files to be prepended with date and time
+# see https://alembic.sqlalchemy.org/en/latest/tutorial.html#editing-the-ini-file
+# for all available tokens
+# file_template = %%(year)d_%%(month).2d_%%(day).2d_%%(hour).2d%%(minute).2d-%%(rev)s_%%(slug)s
+# Or organize into date-based subdirectories (requires recursive_version_locations = true)
+# file_template = %%(year)d/%%(month).2d/%%(day).2d_%%(hour).2d%%(minute).2d_%%(second).2d_%%(rev)s_%%(slug)s
+
+# sys.path path, will be prepended to sys.path if present.
+# defaults to the current working directory.  for multiple paths, the path separator
+# is defined by "path_separator" below.
+prepend_sys_path = .
+
+
+# timezone to use when rendering the date within the migration file
+# as well as the filename.
+# If specified, requires the tzdata library which can be installed by adding
+# `alembic[tz]` to the pip requirements.
+# string value is passed to ZoneInfo()
+# leave blank for localtime
+# timezone =
+
+# max length of characters to apply to the "slug" field
+# truncate_slug_length = 40
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+# set to 'true' to allow .pyc and .pyo files without
+# a source .py file to be detected as revisions in the
+# versions/ directory
+# sourceless = false
+
+# version location specification; This defaults
+# to <script_location>/versions.  When using multiple version
+# directories, initial revisions must be specified with --version-path.
+# The path separator used here should be the separator specified by "path_separator"
+# below.
+# version_locations = %(here)s/bar:%(here)s/bat:%(here)s/alembic/versions
+
+# path_separator; This indicates what character is used to split lists of file
+# paths, including version_locations and prepend_sys_path within configparser
+# files such as alembic.ini.
+# The default rendered in new alembic.ini files is "os", which uses os.pathsep
+# to provide os-dependent path splitting.
+#
+# Note that in order to support legacy alembic.ini files, this default does NOT
+# take place if path_separator is not present in alembic.ini.  If this
+# option is omitted entirely, fallback logic is as follows:
+#
+# 1. Parsing of the version_locations option falls back to using the legacy
+#    "version_path_separator" key, which if absent then falls back to the legacy
+#    behavior of splitting on spaces and/or commas.
+# 2. Parsing of the prepend_sys_path option falls back to the legacy
+#    behavior of splitting on spaces, commas, or colons.
+#
+# Valid values for path_separator are:
+#
+# path_separator = :
+# path_separator = ;
+# path_separator = space
+# path_separator = newline
+#
+# Use os.pathsep. Default configuration used for new projects.
+path_separator = os
+
+# set to 'true' to search source files recursively
+# in each "version_locations" directory
+# new in Alembic version 1.10
+# recursive_version_locations = false
+
+# the output encoding used when revision files
+# are written from script.py.mako
+# output_encoding = utf-8
+
+# database URL.  This is consumed by the user-maintained env.py script only.
+# other means of configuring database URLs may be customized within the env.py
+# file.
+sqlalchemy.url = driver://user:pass@localhost/dbname
+
+
+[post_write_hooks]
+# post_write_hooks defines scripts or Python functions that are run
+# on newly generated revision scripts.  See the documentation for further
+# detail and examples
+
+# format using "black" - use the console_scripts runner, against the "black" entrypoint
+# hooks = black
+# black.type = console_scripts
+# black.entrypoint = black
+# black.options = -l 79 REVISION_SCRIPT_FILENAME
+
+# lint with attempts to fix using "ruff" - use the module runner, against the "ruff" module
+# hooks = ruff
+# ruff.type = module
+# ruff.module = ruff
+# ruff.options = check --fix REVISION_SCRIPT_FILENAME
+
+# Alternatively, use the exec runner to execute a binary found on your PATH
+# hooks = ruff
+# ruff.type = exec
+# ruff.executable = ruff
+# ruff.options = check --fix REVISION_SCRIPT_FILENAME
+
+# Logging configuration.  This is also consumed by the user-maintained
+# env.py script only.
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARNING
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARNING
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S
diff --git a/packages/meshbay-hub/src/meshbay_hub/db/__init__.py b/packages/meshbay-hub/src/meshbay_hub/db/__init__.py
index e69de29..5ef1d3c 100644
--- a/packages/meshbay-hub/src/meshbay_hub/db/__init__.py
+++ b/packages/meshbay-hub/src/meshbay_hub/db/__init__.py
@@ -0,0 +1,9 @@
+"""Hub database layer."""
+from .engine import init_db, close_db, get_db
+from .models import Base, User, Node, Group, GroupMember, GEKBundle, RefreshToken, IPLog
+
+__all__ = [
+    "init_db", "close_db", "get_db",
+    "Base", "User", "Node", "Group", "GroupMember",
+    "GEKBundle", "RefreshToken", "IPLog",
+]
diff --git a/packages/meshbay-hub/src/meshbay_hub/db/engine.py b/packages/meshbay-hub/src/meshbay_hub/db/engine.py
new file mode 100644
index 0000000..6ed5238
--- /dev/null
+++ b/packages/meshbay-hub/src/meshbay_hub/db/engine.py
@@ -0,0 +1,78 @@
+"""
+MeshBay Hub — async SQLAlchemy engine and session factory.
+
+DATABASE_URL env var controls which DB is used:
+  Production:  postgresql+asyncpg://user:pass@localhost/meshbay_hub
+  Tests:       sqlite+aiosqlite:///:memory:   (default if not set)
+"""
+
+import os
+from collections.abc import AsyncGenerator
+
+from sqlalchemy.ext.asyncio import (
+    AsyncEngine,
+    AsyncSession,
+    async_sessionmaker,
+    create_async_engine,
+)
+
+from meshbay_hub.db.models import Base
+
+_DEFAULT_URL = "sqlite+aiosqlite:///:memory:"
+
+def _database_url() -> str:
+    return os.environ.get("MESHBAY_DATABASE_URL", _DEFAULT_URL)
+
+# Module-level engine and session factory (initialised in lifespan)
+_engine: AsyncEngine | None = None
+_session_factory: async_sessionmaker[AsyncSession] | None = None
+
+
+def get_engine() -> AsyncEngine:
+    if _engine is None:
+        raise RuntimeError("DB engine not initialised — call init_db() first")
+    return _engine
+
+
+def get_session_factory() -> async_sessionmaker[AsyncSession]:
+    if _session_factory is None:
+        raise RuntimeError("DB not initialised — call init_db() first")
+    return _session_factory
+
+
+async def init_db(url: str | None = None) -> AsyncEngine:
+    """Create engine, session factory, and all tables (idempotent)."""
+    global _engine, _session_factory
+
+    db_url = url or _database_url()
+    connect_args = {}
+    if db_url.startswith("sqlite"):
+        connect_args["check_same_thread"] = False
+
+    _engine = create_async_engine(
+        db_url,
+        echo=False,
+        connect_args=connect_args,
+    )
+    _session_factory = async_sessionmaker(
+        _engine, expire_on_commit=False, class_=AsyncSession)
+
+    async with _engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)
+
+    return _engine
+
+
+async def close_db() -> None:
+    global _engine, _session_factory
+    if _engine:
+        await _engine.dispose()
+        _engine = None
+        _session_factory = None
+
+
+async def get_db() -> AsyncGenerator[AsyncSession, None]:
+    """FastAPI dependency — yields an async DB session."""
+    factory = get_session_factory()
+    async with factory() as session:
+        yield session
diff --git a/packages/meshbay-hub/src/meshbay_hub/db/migrations/README b/packages/meshbay-hub/src/meshbay_hub/db/migrations/README
new file mode 100644
index 0000000..98e4f9c
--- /dev/null
+++ b/packages/meshbay-hub/src/meshbay_hub/db/migrations/README
@@ -0,0 +1 @@
+Generic single-database configuration.
\ No newline at end of file
diff --git a/packages/meshbay-hub/src/meshbay_hub/db/migrations/env.py b/packages/meshbay-hub/src/meshbay_hub/db/migrations/env.py
new file mode 100644
index 0000000..f572716
--- /dev/null
+++ b/packages/meshbay-hub/src/meshbay_hub/db/migrations/env.py
@@ -0,0 +1,65 @@
+"""Alembic env.py — async-aware, reads DATABASE_URL from environment."""
+
+import asyncio
+import os
+from logging.config import fileConfig
+
+from sqlalchemy import pool
+from sqlalchemy.engine import Connection
+from sqlalchemy.ext.asyncio import async_engine_from_config
+
+from alembic import context
+
+from meshbay_hub.db.models import Base
+
+config = context.config
+
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+target_metadata = Base.metadata
+
+# Allow override via env var (production uses asyncpg, tests may use aiosqlite)
+db_url = os.environ.get(
+    "MESHBAY_DATABASE_URL",
+    "postgresql+asyncpg://meshbay:meshbay@localhost/meshbay_hub",
+)
+config.set_main_option("sqlalchemy.url", db_url)
+
+
+def run_migrations_offline() -> None:
+    context.configure(
+        url=db_url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def do_run_migrations(connection: Connection) -> None:
+    context.configure(connection=connection, target_metadata=target_metadata)
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+async def run_async_migrations() -> None:
+    connectable = async_engine_from_config(
+        config.get_section(config.config_ini_section, {}),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+    async with connectable.connect() as connection:
+        await connection.run_sync(do_run_migrations)
+    await connectable.dispose()
+
+
+def run_migrations_online() -> None:
+    asyncio.run(run_async_migrations())
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()
diff --git a/packages/meshbay-hub/src/meshbay_hub/db/migrations/script.py.mako b/packages/meshbay-hub/src/meshbay_hub/db/migrations/script.py.mako
new file mode 100644
index 0000000..1101630
--- /dev/null
+++ b/packages/meshbay-hub/src/meshbay_hub/db/migrations/script.py.mako
@@ -0,0 +1,28 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision: str = ${repr(up_revision)}
+down_revision: Union[str, Sequence[str], None] = ${repr(down_revision)}
+branch_labels: Union[str, Sequence[str], None] = ${repr(branch_labels)}
+depends_on: Union[str, Sequence[str], None] = ${repr(depends_on)}
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    ${downgrades if downgrades else "pass"}
diff --git a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/d28b9caf9f07_initial_schema.py b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/d28b9caf9f07_initial_schema.py
new file mode 100644
index 0000000..d4a9aa6
--- /dev/null
+++ b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/d28b9caf9f07_initial_schema.py
@@ -0,0 +1,127 @@
+"""initial_schema
+
+Revision ID: d28b9caf9f07
+Revises: 
+Create Date: 2026-08-09 04:35:07.120021
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'd28b9caf9f07'
+down_revision: Union[str, Sequence[str], None] = None
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('users',
+    sa.Column('id', sa.String(length=36), nullable=False),
+    sa.Column('username', sa.String(length=64), nullable=False),
+    sa.Column('email', sa.String(length=256), nullable=False),
+    sa.Column('pw_hash', sa.LargeBinary(), nullable=False),
+    sa.Column('pw_salt', sa.LargeBinary(), nullable=False),
+    sa.Column('pk_ed25519', sa.String(length=64), nullable=False),
+    sa.Column('pk_x25519', sa.String(length=64), nullable=False),
+    sa.Column('hub_id', sa.String(length=128), nullable=False),
+    sa.Column('status', sa.String(length=16), nullable=False),
+    sa.Column('created_at', sa.DateTime(timezone=True), nullable=False),
+    sa.PrimaryKeyConstraint('id'),
+    sa.UniqueConstraint('username')
+    )
+    op.create_index('ix_users_email', 'users', ['email'], unique=False)
+    op.create_index('ix_users_username', 'users', ['username'], unique=False)
+    op.create_table('groups',
+    sa.Column('id', sa.String(length=36), nullable=False),
+    sa.Column('name', sa.String(length=128), nullable=False),
+    sa.Column('admin_id', sa.String(length=36), nullable=False),
+    sa.Column('visibility', sa.String(length=16), nullable=False),
+    sa.Column('join_policy', sa.String(length=16), nullable=False),
+    sa.Column('status', sa.String(length=16), nullable=False),
+    sa.Column('created_at', sa.DateTime(timezone=True), nullable=False),
+    sa.ForeignKeyConstraint(['admin_id'], ['users.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index('ix_groups_name', 'groups', ['name'], unique=False)
+    op.create_table('ip_logs',
+    sa.Column('id', sa.Integer(), autoincrement=True, nullable=False),
+    sa.Column('user_id', sa.String(length=36), nullable=True),
+    sa.Column('event', sa.String(length=32), nullable=False),
+    sa.Column('ip_address', sa.String(length=45), nullable=False),
+    sa.Column('detail', sa.String(length=256), nullable=True),
+    sa.Column('timestamp', sa.DateTime(timezone=True), nullable=False),
+    sa.ForeignKeyConstraint(['user_id'], ['users.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index('ix_ip_logs_ip', 'ip_logs', ['ip_address'], unique=False)
+    op.create_index('ix_ip_logs_timestamp', 'ip_logs', ['timestamp'], unique=False)
+    op.create_index('ix_ip_logs_user_id', 'ip_logs', ['user_id'], unique=False)
+    op.create_table('nodes',
+    sa.Column('id', sa.String(length=36), nullable=False),
+    sa.Column('user_id', sa.String(length=36), nullable=False),
+    sa.Column('pk_node', sa.String(length=64), nullable=False),
+    sa.Column('endpoint_hint', sa.String(length=128), nullable=True),
+    sa.Column('announced_at', sa.DateTime(timezone=True), nullable=False),
+    sa.ForeignKeyConstraint(['user_id'], ['users.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index('ix_nodes_user_id', 'nodes', ['user_id'], unique=False)
+    op.create_table('refresh_tokens',
+    sa.Column('id', sa.String(length=36), nullable=False),
+    sa.Column('user_id', sa.String(length=36), nullable=False),
+    sa.Column('token_hash', sa.String(length=64), nullable=False),
+    sa.Column('expires_at', sa.DateTime(timezone=True), nullable=False),
+    sa.Column('created_at', sa.DateTime(timezone=True), nullable=False),
+    sa.Column('revoked', sa.Boolean(), nullable=False),
+    sa.ForeignKeyConstraint(['user_id'], ['users.id'], ),
+    sa.PrimaryKeyConstraint('id'),
+    sa.UniqueConstraint('token_hash')
+    )
+    op.create_index('ix_refresh_tokens_hash', 'refresh_tokens', ['token_hash'], unique=False)
+    op.create_table('gek_bundles',
+    sa.Column('group_id', sa.String(length=36), nullable=False),
+    sa.Column('user_id', sa.String(length=36), nullable=False),
+    sa.Column('pk_eph_b64', sa.String(length=64), nullable=False),
+    sa.Column('nonce_b64', sa.String(length=32), nullable=False),
+    sa.Column('wrapped_b64', sa.String(length=128), nullable=False),
+    sa.Column('stored_at', sa.DateTime(timezone=True), nullable=False),
+    sa.ForeignKeyConstraint(['group_id'], ['groups.id'], ),
+    sa.ForeignKeyConstraint(['user_id'], ['users.id'], ),
+    sa.PrimaryKeyConstraint('group_id', 'user_id')
+    )
+    op.create_table('group_members',
+    sa.Column('group_id', sa.String(length=36), nullable=False),
+    sa.Column('user_id', sa.String(length=36), nullable=False),
+    sa.Column('joined_at', sa.DateTime(timezone=True), nullable=False),
+    sa.ForeignKeyConstraint(['group_id'], ['groups.id'], ),
+    sa.ForeignKeyConstraint(['user_id'], ['users.id'], ),
+    sa.PrimaryKeyConstraint('group_id', 'user_id')
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_table('group_members')
+    op.drop_table('gek_bundles')
+    op.drop_index('ix_refresh_tokens_hash', table_name='refresh_tokens')
+    op.drop_table('refresh_tokens')
+    op.drop_index('ix_nodes_user_id', table_name='nodes')
+    op.drop_table('nodes')
+    op.drop_index('ix_ip_logs_user_id', table_name='ip_logs')
+    op.drop_index('ix_ip_logs_timestamp', table_name='ip_logs')
+    op.drop_index('ix_ip_logs_ip', table_name='ip_logs')
+    op.drop_table('ip_logs')
+    op.drop_index('ix_groups_name', table_name='groups')
+    op.drop_table('groups')
+    op.drop_index('ix_users_username', table_name='users')
+    op.drop_index('ix_users_email', table_name='users')
+    op.drop_table('users')
+    # ### end Alembic commands ###
diff --git a/packages/meshbay-hub/src/meshbay_hub/db/models.py b/packages/meshbay-hub/src/meshbay_hub/db/models.py
new file mode 100644
index 0000000..3814f2e
--- /dev/null
+++ b/packages/meshbay-hub/src/meshbay_hub/db/models.py
@@ -0,0 +1,167 @@
+"""
+MeshBay Hub — SQLAlchemy 2.0 ORM models.
+
+Tables:
+  users         — registered users (identity + public keys)
+  nodes         — node announcements
+  groups        — group registry
+  group_members — group membership
+  gek_bundles   — encrypted GEK per (group, user)
+  refresh_tokens — hashed refresh tokens
+  ip_logs       — connection log for legal compliance (1-year retention)
+"""
+
+import uuid
+from datetime import datetime, timezone
+
+from sqlalchemy import (
+    Boolean, DateTime, ForeignKey, Index, Integer,
+    String, Text, UniqueConstraint,
+)
+from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, relationship
+
+
+def _now() -> datetime:
+    return datetime.now(timezone.utc)
+
+def _uuid() -> str:
+    return str(uuid.uuid4())
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+# ── Users ─────────────────────────────────────────────────────────────────────
+
+class User(Base):
+    __tablename__ = "users"
+
+    id:          Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
+    username:    Mapped[str] = mapped_column(String(64), unique=True, nullable=False)
+    email:       Mapped[str] = mapped_column(String(256), nullable=False)   # kept for recovery
+    pw_hash:     Mapped[bytes] = mapped_column(nullable=False)
+    pw_salt:     Mapped[bytes] = mapped_column(nullable=False)
+    pk_ed25519:  Mapped[str] = mapped_column(String(64), nullable=False)    # base64 raw 32B
+    pk_x25519:   Mapped[str] = mapped_column(String(64), nullable=False)    # base64 raw 32B
+    hub_id:      Mapped[str] = mapped_column(String(128), nullable=False)
+    status:      Mapped[str] = mapped_column(String(16), default="active")  # active|suspended|revoked
+    created_at:  Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_now)
+
+    nodes:         Mapped[list["Node"]]         = relationship(back_populates="user")
+    group_memberships: Mapped[list["GroupMember"]] = relationship(back_populates="user")
+    gek_bundles:   Mapped[list["GEKBundle"]]    = relationship(back_populates="user")
+    refresh_tokens: Mapped[list["RefreshToken"]] = relationship(back_populates="user")
+    ip_logs:       Mapped[list["IPLog"]]        = relationship(back_populates="user")
+
+    __table_args__ = (
+        Index("ix_users_username", "username"),
+        Index("ix_users_email", "email"),
+    )
+
+
+# ── Nodes ─────────────────────────────────────────────────────────────────────
+
+class Node(Base):
+    __tablename__ = "nodes"
+
+    id:            Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
+    user_id:       Mapped[str] = mapped_column(ForeignKey("users.id"), nullable=False)
+    pk_node:       Mapped[str] = mapped_column(String(64), nullable=False)  # Ed25519 b64
+    endpoint_hint: Mapped[str | None] = mapped_column(String(128))          # "ip:port" or null
+    announced_at:  Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_now)
+
+    user: Mapped["User"] = relationship(back_populates="nodes")
+
+    __table_args__ = (Index("ix_nodes_user_id", "user_id"),)
+
+
+# ── Groups ────────────────────────────────────────────────────────────────────
+
+class Group(Base):
+    __tablename__ = "groups"
+
+    id:          Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
+    name:        Mapped[str] = mapped_column(String(128), nullable=False)
+    admin_id:    Mapped[str] = mapped_column(ForeignKey("users.id"), nullable=False)
+    visibility:  Mapped[str] = mapped_column(String(16), default="private")   # public|private
+    join_policy: Mapped[str] = mapped_column(String(16), default="invite")    # open|request|invite
+    status:      Mapped[str] = mapped_column(String(16), default="active")    # active|revoked
+    created_at:  Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_now)
+
+    members:     Mapped[list["GroupMember"]] = relationship(back_populates="group")
+    gek_bundles: Mapped[list["GEKBundle"]]   = relationship(back_populates="group")
+
+    __table_args__ = (Index("ix_groups_name", "name"),)
+
+
+class GroupMember(Base):
+    __tablename__ = "group_members"
+
+    group_id:  Mapped[str] = mapped_column(ForeignKey("groups.id"), primary_key=True)
+    user_id:   Mapped[str] = mapped_column(ForeignKey("users.id"),  primary_key=True)
+    joined_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_now)
+
+    group: Mapped["Group"] = relationship(back_populates="members")
+    user:  Mapped["User"]  = relationship(back_populates="group_memberships")
+
+
+# ── GEK bundles ───────────────────────────────────────────────────────────────
+
+class GEKBundle(Base):
+    """Encrypted GEK bundle — opaque to the hub (hub cannot decrypt it)."""
+    __tablename__ = "gek_bundles"
+
+    group_id:   Mapped[str] = mapped_column(ForeignKey("groups.id"), primary_key=True)
+    user_id:    Mapped[str] = mapped_column(ForeignKey("users.id"),  primary_key=True)
+    pk_eph_b64:  Mapped[str] = mapped_column(String(64), nullable=False)
+    nonce_b64:   Mapped[str] = mapped_column(String(32), nullable=False)
+    wrapped_b64: Mapped[str] = mapped_column(String(128), nullable=False)
+    stored_at:  Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_now)
+
+    group: Mapped["Group"] = relationship(back_populates="gek_bundles")
+    user:  Mapped["User"]  = relationship(back_populates="gek_bundles")
+
+
+# ── Refresh tokens ────────────────────────────────────────────────────────────
+
+class RefreshToken(Base):
+    __tablename__ = "refresh_tokens"
+
+    id:         Mapped[str] = mapped_column(String(36), primary_key=True, default=_uuid)
+    user_id:    Mapped[str] = mapped_column(ForeignKey("users.id"), nullable=False)
+    token_hash: Mapped[str] = mapped_column(String(64), unique=True, nullable=False)  # blake3 hex
+    expires_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_now)
+    revoked:    Mapped[bool] = mapped_column(Boolean, default=False)
+
+    user: Mapped["User"] = relationship(back_populates="refresh_tokens")
+
+    __table_args__ = (Index("ix_refresh_tokens_hash", "token_hash"),)
+
+
+# ── IP logs (legal compliance) ────────────────────────────────────────────────
+
+class IPLog(Base):
+    """
+    Connection log for legal compliance.
+    Retention: minimum 1 year (LCEN / EU e-Commerce Directive).
+    Events: account_create, login, login_fail, group_create, group_join, group_leave,
+            node_announce, token_refresh.
+    """
+    __tablename__ = "ip_logs"
+
+    id:         Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    user_id:    Mapped[str | None] = mapped_column(ForeignKey("users.id"))   # null for failed logins
+    event:      Mapped[str] = mapped_column(String(32), nullable=False)
+    ip_address: Mapped[str] = mapped_column(String(45), nullable=False)       # IPv4 or IPv6
+    detail:     Mapped[str | None] = mapped_column(String(256))               # e.g. username on fail
+    timestamp:  Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_now)
+
+    user: Mapped["User | None"] = relationship(back_populates="ip_logs")
+
+    __table_args__ = (
+        Index("ix_ip_logs_user_id", "user_id"),
+        Index("ix_ip_logs_timestamp", "timestamp"),
+        Index("ix_ip_logs_ip", "ip_address"),
+    )