style: ruff's own fixes, mechanically applied

`ruff check .` had gone unrun long enough to report 568 errors, which is the
same as having no linter: the next real finding would have been invisible in the
noise. This is the 521 it fixes by itself, in 173 files, and nothing else — the
98 it cannot fix are the next commit.

What actually changed: import sorting (225), imports nobody used (87, none of
them a re-export — no `__init__.py` is touched, which was the one way this could
have broken an import elsewhere), `datetime.timezone.utc` to `datetime.UTC` (69)
and `asyncio.TimeoutError` to `TimeoutError` (18), both plain aliases on the 3.12
this project requires, `Optional[X]` to `X | None` (24), and f-strings with
nothing to interpolate (19).

Checked rather than assumed: every module in the three packages still imports,
and the suite is 2893 passed — the same count, test for test, as the merge
before it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

8 files changed, 38 insertions, 44 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/a7b8c9d0e1f2_add_group_last_activity.py b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/a7b8c9d0e1f2_add_group_last_activity.py
index 8a4e2ee..034d12f 100644
--- a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/a7b8c9d0e1f2_add_group_last_activity.py
+++ b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/a7b8c9d0e1f2_add_group_last_activity.py
@@ -5,16 +5,15 @@ Revises: f1a2b3c4d5e6
 Create Date: 2026-08-20 20:50:00.000000
 
 """
-from typing import Sequence, Union
+from collections.abc import Sequence
 
-from alembic import op
 import sqlalchemy as sa
-
+from alembic import op
 
 revision: str = 'a7b8c9d0e1f2'
-down_revision: Union[str, Sequence[str], None] = 'f1a2b3c4d5e6'
-branch_labels: Union[str, Sequence[str], None] = None
-depends_on: Union[str, Sequence[str], None] = None
+down_revision: str | Sequence[str] | None = 'f1a2b3c4d5e6'
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
 
 
 def upgrade() -> None:
diff --git a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/a9b8c7d6e5f4_add_login_throttle.py b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/a9b8c7d6e5f4_add_login_throttle.py
index 2fead6c..45985e2 100644
--- a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/a9b8c7d6e5f4_add_login_throttle.py
+++ b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/a9b8c7d6e5f4_add_login_throttle.py
@@ -7,15 +7,15 @@ Revision ID: a9b8c7d6e5f4
 Revises: e5f6a7b8c9d0
 """
 
-from typing import Sequence, Union
+from collections.abc import Sequence
 
 import sqlalchemy as sa
 from alembic import op
 
 revision: str = "a9b8c7d6e5f4"
-down_revision: Union[str, Sequence[str], None] = "e5f6a7b8c9d0"
-branch_labels: Union[str, Sequence[str], None] = None
-depends_on: Union[str, Sequence[str], None] = None
+down_revision: str | Sequence[str] | None = "e5f6a7b8c9d0"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
 
 
 def upgrade() -> None:
diff --git a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/b1c2d3e4f5a6_add_hub_settings.py b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/b1c2d3e4f5a6_add_hub_settings.py
index 13f2b5c..9a90f7a 100644
--- a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/b1c2d3e4f5a6_add_hub_settings.py
+++ b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/b1c2d3e4f5a6_add_hub_settings.py
@@ -5,16 +5,15 @@ Revises: a7b8c9d0e1f2
 Create Date: 2026-08-28 12:00:00.000000
 
 """
-from typing import Sequence, Union
+from collections.abc import Sequence
 
-from alembic import op
 import sqlalchemy as sa
-
+from alembic import op
 
 revision: str = 'b1c2d3e4f5a6'
-down_revision: Union[str, Sequence[str], None] = 'a7b8c9d0e1f2'
-branch_labels: Union[str, Sequence[str], None] = None
-depends_on: Union[str, Sequence[str], None] = None
+down_revision: str | Sequence[str] | None = 'a7b8c9d0e1f2'
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
 
 
 def upgrade() -> None:
diff --git a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/c3d4e5f6a7b8_group_name_unique_per_owner.py b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/c3d4e5f6a7b8_group_name_unique_per_owner.py
index 6fc5b73..fea0583 100644
--- a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/c3d4e5f6a7b8_group_name_unique_per_owner.py
+++ b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/c3d4e5f6a7b8_group_name_unique_per_owner.py
@@ -10,16 +10,15 @@ its UUID — this only makes `name@owner` a dependable handle.
 Pre-flight: abort if the data already violates it, with the offending
 (admin_id, name) pairs listed, rather than silently renaming anyone's group.
 """
-from typing import Sequence, Union
+from collections.abc import Sequence
 
-from alembic import op
 import sqlalchemy as sa
-
+from alembic import op
 
 revision: str = 'c3d4e5f6a7b8'
-down_revision: Union[str, Sequence[str], None] = 'b1c2d3e4f5a6'
-branch_labels: Union[str, Sequence[str], None] = None
-depends_on: Union[str, Sequence[str], None] = None
+down_revision: str | Sequence[str] | None = 'b1c2d3e4f5a6'
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
 
 
 def upgrade() -> None:
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
index 6301426..a814f37 100644
--- 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
@@ -12,16 +12,15 @@ Revises:
 Create Date: 2026-08-09 04:35:07.120021
 
 """
-from typing import Sequence, Union
+from collections.abc import Sequence
 
-from alembic import op
 import sqlalchemy as sa
-
+from alembic import op
 
 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
+down_revision: str | Sequence[str] | None = None
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
 
 
 def upgrade() -> None:
diff --git a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/d4e5f6a7b8c9_add_email_verification.py b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/d4e5f6a7b8c9_add_email_verification.py
index 6741eb8..aa15b6d 100644
--- a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/d4e5f6a7b8c9_add_email_verification.py
+++ b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/d4e5f6a7b8c9_add_email_verification.py
@@ -9,16 +9,15 @@ Revises: c3d4e5f6a7b8
 Create Date: 2026-08-31 14:00:00.000000
 
 """
-from typing import Sequence, Union
+from collections.abc import Sequence
 
-from alembic import op
 import sqlalchemy as sa
-
+from alembic import op
 
 revision: str = 'd4e5f6a7b8c9'
-down_revision: Union[str, Sequence[str], None] = 'c3d4e5f6a7b8'
-branch_labels: Union[str, Sequence[str], None] = None
-depends_on: Union[str, Sequence[str], None] = None
+down_revision: str | Sequence[str] | None = 'c3d4e5f6a7b8'
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
 
 
 def upgrade() -> None:
diff --git a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/e5f6a7b8c9d0_add_mail_quota.py b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/e5f6a7b8c9d0_add_mail_quota.py
index 8f2e4d2..c729de4 100644
--- a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/e5f6a7b8c9d0_add_mail_quota.py
+++ b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/e5f6a7b8c9d0_add_mail_quota.py
@@ -8,15 +8,15 @@ Revision ID: e5f6a7b8c9d0
 Revises: d4e5f6a7b8c9
 """
 
-from typing import Sequence, Union
+from collections.abc import Sequence
 
 import sqlalchemy as sa
 from alembic import op
 
 revision: str = "e5f6a7b8c9d0"
-down_revision: Union[str, Sequence[str], None] = "d4e5f6a7b8c9"
-branch_labels: Union[str, Sequence[str], None] = None
-depends_on: Union[str, Sequence[str], None] = None
+down_revision: str | Sequence[str] | None = "d4e5f6a7b8c9"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
 
 
 def upgrade() -> None:
diff --git a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/f1a2b3c4d5e6_add_user_preferences.py b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/f1a2b3c4d5e6_add_user_preferences.py
index e30a4da..9f8e729 100644
--- a/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/f1a2b3c4d5e6_add_user_preferences.py
+++ b/packages/meshbay-hub/src/meshbay_hub/db/migrations/versions/f1a2b3c4d5e6_add_user_preferences.py
@@ -5,16 +5,15 @@ Revises: d28b9caf9f07
 Create Date: 2026-08-19 12:00:00.000000
 
 """
-from typing import Sequence, Union
+from collections.abc import Sequence
 
-from alembic import op
 import sqlalchemy as sa
-
+from alembic import op
 
 revision: str = 'f1a2b3c4d5e6'
-down_revision: Union[str, Sequence[str], None] = 'd28b9caf9f07'
-branch_labels: Union[str, Sequence[str], None] = None
-depends_on: Union[str, Sequence[str], None] = None
+down_revision: str | Sequence[str] | None = 'd28b9caf9f07'
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
 
 
 def upgrade() -> None: