fix(lint): E402 is on — the ignore meant for main.py had let 11 late imports in elsewhere

ruff.toml ignored E402 everywhere for main.py's logging setup. Measured: 28 hits, of which 11
had nothing to do with it — runner.py's logger line between its imports, models.py importing
canonical_email mid-file, a test constant above its imports, and main.py's own third-party and
mimetypes imports. Those are moved up. What stays after configure_logging in main.py is marked
per statement (noqa E402, logging is configured first), its comment now says why the order
matters (a line logged while importing, not the logger's creation). The register row goes, the
ruff key whitelist loses ignore, and a late import is red again. The T20 comment counts the
third deliberate print (scripts/e2e_seed.py).

backend/app/models.py

@@ -23,6 +23,7 @@ from sqlalchemy.dialects.postgresql import JSONB, TSVECTOR
 from sqlalchemy.orm import Mapped, mapped_column, relationship, validates
 
 from app.db import Base
+from app.utils import canonical_email
 
 # Every user-supplied display string in this schema shares one width, and it lives HERE so the
 # columns below are declared with it rather than with a literal: a name a person typed goes into
@@ -51,9 +52,6 @@ def display_text(raw: str | None) -> str | None:
     return (raw or "").strip()[:DISPLAY_TEXT_MAX] or None
 
 
-from app.utils import canonical_email
-
-
 # The resume-position columns (VideoState / PlexState.position_seconds) are int4. The checkpoint
 # routes bound their bodies by this, so an out-of-range position is a 422 rather than a 500.
 POSITION_MAX_S = 2**31 - 1