T10.3 fix - the drop migration was deleting every project membership

Found by actually seeding the pre-migration schema and rolling forward, rather
than by checking that the column disappeared. The column disappeared correctly;
project_members came back empty.

batch_alter_table emulates ALTER on SQLite by rebuilding the table - create a
new one, copy the rows, DROP the original, rename. server/alembic/env.py:22
imports the engine from server/db.py, which registers a connect listener
setting PRAGMA foreign_keys=ON, so that DROP TABLE cascaded through
project_members.user_id (ondelete="CASCADE") and took every membership row with
it. No error, nothing in the log, and the users table looked perfect
afterwards.

Production would have escaped it - Postgres does a real ALTER TABLE DROP COLUMN
and touches nothing else - so this was a local-dev and test-fixture data loss,
which is worse in one specific way: the tests CLAUDE.md requires run against a
throwaway SQLite database, so the suite would have been validating behaviour
against silently emptied membership tables.

Wrapping the batch in PRAGMA foreign_keys=OFF is not the fix: that pragma is a
no-op inside a transaction and alembic runs migrations in one. The rebuild is
simply unnecessary - SQLite has had native ALTER TABLE DROP COLUMN since 3.35
(2021), this runtime has 3.42, and Postgres has always had it. Plain
op.drop_column touches one table and cascades nowhere.

The reasoning is written into the migration's docstring as a DO NOT, because
batch_alter_table is the reflexive thing to reach for when a migration has to
work on SQLite and the failure is invisible.

Re-verified with memberships in the fixture:

  3/3 users survive, roles intact (admin still admin)
  2/2 project_members survive
  downgrade -1 -> column back, nullable; upgrade -> gone again

Also closed BL-026: notify.send_now removed. Nothing referenced it and its
docstring described itself entirely in terms of password resets. send_email,
which it wrapped, is untouched and still used by the outbox.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

server/notify.py

@@ -121,22 +121,6 @@ def send_email(s: dict, to_addr: str, subject: str, body: str) -> None:
         srv.send_message(msg)
 
 
-def send_now(db: Session, to_addr: str, subject: str, body: str) -> bool:
-    """Send one email immediately, outside the outbox. Used for password resets —
-    a reset link must never sit in a queue, and it must not be persisted in the
-    notifications table where an admin could read it and take over the account.
-    Returns True if it went out."""
-    s = get_settings(db)
-    if not (s.get("email_enabled") and smtp_ready(s) and to_addr):
-        return False
-    try:
-        send_email(s, to_addr, subject, body)
-        return True
-    except Exception as e:  # noqa: BLE001 — never surface SMTP detail to the caller
-        log.warning("password-reset email to %s failed: %s", to_addr, e)
-        return False
-
-
 def enqueue(db: Session, *, user: "models.User", kind: str, subject: str, body: str,
             link: str = "", wp_id: Optional[str] = None, project_id: Optional[str] = None) -> "models.Notification":
     """Record a notification. Marked 'pending' only if email is enabled + SMTP ready +