Fix ruff lint errors across codebase

- Auto-fix F401 (unused imports) and I001 (unsorted imports) with ruff --fix
- Manually fix E501 (line too long) in alembic migrations and src/ models
- Run ruff format to ensure consistent formatting

Co-Authored-By: Paperclip <noreply@paperclip.ing>

alembic/versions/006_email_inbound_token_server_default.py

@@ -6,6 +6,7 @@ Create Date: 2026-04-04
 """
 
 import sqlalchemy as sa
+
 from alembic import op
 
 revision = "006_email_inbound_token_server_default"
@@ -29,7 +30,8 @@ def upgrade() -> None:
         "users",
         "email_inbound_token",
         server_default=sa.text(
-            "replace(replace(trim(trailing '=' from encode(gen_random_bytes(16), 'base64')), '+', '-'), '/', '_')"
+            "replace(replace(trim(trailing '=' from "
+            "encode(gen_random_bytes(16), 'base64')), '+', '-'), '/', '_')"
         ),
     )