refactor(logs): name every logger after its module, and hold it there

25 literal names covered 34 modules. plex/client.py, plex/stream.py,
plex/subtitles.py, plex/sync.py and two Plex route modules all called themselves
`siftlode.plex`; downloads/pipeline.py called itself `siftlode.worker`;
routes/channels.py called itself `siftlode.api`. The `logger` column is in every
stored row so E22.6's console can filter on it, and so an operator can pin a level
to one part of the system — neither works when six modules share a name.

`logs.get_logger(__name__)` derives it: app/plex/sync.py -> siftlode.plex.sync.
One name per module, and it cannot drift from the file it sits in.
tests/test_logger_names.py pins the derivation, that everything stays under the
one `siftlode` tree the handler and the tests attach to, and that no module
hand-rolls a name again unless the line says why (`# logger-name-ok: <why>`).
Two do: get_logger's own call, and `siftlode.http`, which is named for the traffic
it carries rather than the module it lives in — it replaced uvicorn's access log
and is what an operator pins when they want request lines and nothing else.

app/scheduler.py called its logger `logger`; every other module calls it `log`.

ruff gains LOG, G, T20, TRY400, TRY401 and S112. Four findings cleared with them:
worker.py logged `str(exc)[:120]` where the traceback was the whole question, and
three prints/f-strings that are deliberate now say so on the line. S110 and BLE001
stay off until S3 — 23 handlers are outstanding and each is a judgement about one
of them; enabling the rules first would just mean 23 blanket noqas.

backend/app/downloads/backfill.py

@@ -11,12 +11,12 @@ Run once per environment:
     docker exec siftlode-worker-1 python -c "from app.downloads import backfill; print(backfill.run())"
 """
 
-import logging
 from urllib.parse import urlsplit
 
 import yt_dlp
 from sqlalchemy import select
 
+from app import logs
 from app.config import settings
 from app.db import SessionLocal
 from app.downloads import adapters
@@ -24,7 +24,7 @@ from app.downloads import edit as editmod
 from app.downloads import formats, service
 from app.models import MediaAsset
 
-log = logging.getLogger("siftlode.backfill")
+log = logs.get_logger(__name__)
 
 
 def _extract_meta(url: str, adapter: adapters.SourceAdapter, asset_id: int) -> dict | None:

backend/app/downloads/credentials.py

@@ -23,19 +23,19 @@ Security controls enforced here:
     logged, or written to a job's error/snapshot.
 """
 
-import logging
 import os
 from pathlib import Path
 
 from sqlalchemy import select
 from sqlalchemy.orm import Session
 
+from app import logs
 from app.downloads import formats
 from app.downloads.adapters import _host_is
 from app.models import DownloadCredential, MediaAsset
 from app.security import decrypt_optional, encrypt
 
-log = logging.getLogger("siftlode.downloads.credentials")
+log = logs.get_logger(__name__)
 
 
 class HostSpec:

backend/app/downloads/edit.py

@@ -23,7 +23,6 @@ for a player hover-preview later.
 
 import hashlib
 import json
-import logging
 import math
 import os
 import queue
@@ -33,9 +32,10 @@ import threading
 import time
 from pathlib import Path
 
+from app import logs
 from app.config import settings
 
-log = logging.getLogger("siftlode.edit")
+log = logs.get_logger(__name__)
 
 
 def encode_thread_cap() -> int:
@@ -368,7 +368,9 @@ def escalate_kill(proc: subprocess.Popen, terminate, kill, grace_s: float, label
     try:
         proc.wait(timeout=grace_s)
     except subprocess.TimeoutExpired:
-        log.error("%s pid %s survived SIGKILL", label, proc.pid)
+        # noqa TRY400: the exception IS the message here. A TimeoutExpired's traceback is this
+        # `wait` call and nothing else — it would add three frames and no fact the line lacks.
+        log.error("%s pid %s survived SIGKILL", label, proc.pid)  # noqa: TRY400
 
 
 def _stop(proc: subprocess.Popen) -> None:

backend/app/downloads/gc.py

@@ -16,7 +16,6 @@ Five passes each run:
 Runs in the API process (which mounts DOWNLOAD_ROOT). Pure disk/DB work — no YouTube quota.
 """
 
-import logging
 import time
 from datetime import datetime, timedelta, timezone
 from pathlib import Path
@@ -24,14 +23,13 @@ from pathlib import Path
 from sqlalchemy import func, select
 from sqlalchemy.orm import Session
 
-from app import sysconfig
+from app import logs, sysconfig
 from app.config import settings
 from app.downloads import storage
 from app.models import DownloadJob, MediaAsset
 from app.notifications import create_notification
 
-log = logging.getLogger("siftlode.downloads.gc")
-
+log = logs.get_logger(__name__)
 # Dot-prefixed top-level trees that are NOT part of the Plex/flat asset layout — the orphan sweep
 # never touches them (user clips, Plex HLS/img caches, in-progress staging, editor storyboards).
 _SYSTEM_TREE = {".edits", ".plex-hls", ".plex-img-cache", ".staging", ".storyboards"}

backend/app/downloads/pipeline.py

@@ -1,6 +1,5 @@
 """Child-side download/edit pipeline — the yt-dlp download + ffmpeg edit that runs in the spawned subprocess."""
 
-import logging
 import re
 import shutil
 import time
@@ -9,7 +8,7 @@ from pathlib import Path
 
 import yt_dlp
 
-from app import sysconfig
+from app import logs, sysconfig
 from app.config import settings
 from app.db import SessionLocal
 from app.downloads import edit as editmod
@@ -29,7 +28,7 @@ from app.models import DownloadJob, MediaAsset
 from app.notifications import create_notification
 from app.titles import normalize_title
 
-log = logging.getLogger("siftlode.worker")
+log = logs.get_logger(__name__)
 
 
 class _Aborted(Exception):

backend/app/downloads/runner.py

@@ -11,7 +11,6 @@ writes the terminal job/asset state itself (done / error, or a cooperative pause
 progress hook), then exits 0. An unexpected crash exits non-zero and the parent fails the job.
 """
 
-import logging
 import os
 import shutil
 import subprocess
@@ -24,7 +23,7 @@ from app.db import SessionLocal
 from app.downloads import edit as editmod
 from app.models import DownloadJob
 
-log = logging.getLogger("siftlode.worker.runner")
+log = logs.get_logger(__name__)
 
 
 def _deprioritize() -> None:
@@ -57,7 +56,11 @@ def main() -> None:
     logs.configure_logging("runner")
     _deprioritize()
     if len(sys.argv) != 2:
-        print("usage: python -m app.downloads.runner <job_id>", file=sys.stderr)
+        # noqa T201: this runs BEFORE configure_logging, and a usage error has to reach the
+        # operator who typed it whether or not logging was ever set up.
+        print(  # noqa: T201
+            "usage: python -m app.downloads.runner <job_id>", file=sys.stderr
+        )
         raise SystemExit(2)
     job_id = int(sys.argv[1])
     # This whole process exists to run ONE job — tag every line it prints with it, so the child's