Add DB viewer access logging, account deletion, and forced password change

Logs a distinct db_viewer_accessed event (not just the earlier
session_created "requested" event) when an admin's browser actually
completes the hand-off into Adminer. Adds a password-confirmed
account-deletion box to Settings, relying on the existing ON DELETE
CASCADE foreign keys to clean up everything the account owns. Adds an
admin-only "require password change" flag that get_current_user
enforces server-side (403 on everything except /auth/me,
/auth/change-password, /auth/logout) - meant for handing a demo
account to someone with a known sample password.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

apps/api/app/repositories/user_repository.py

@@ -23,6 +23,13 @@ class UserRepository:
         result = await self.db.execute(select(User.email).where(User.is_admin.is_(True)))
         return list(result.scalars().all())
 
+    async def delete(self, user: User) -> None:
+        """Cascades (ON DELETE CASCADE, see migrations) to every row the
+        user owns - companies and everything under them, refresh tokens,
+        security events, etc. Irreversible."""
+        await self.db.delete(user)
+        await self.db.flush()
+
     async def create(
         self,
         *,