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>

1 files changed, 65 insertions, 0 deletions

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()