Cleanup only, no behaviour change (ruff clean + pytest 193):
- imports hoisted above `router =` and grouped/sorted (isort) across the split
files; ruff-format pass restores the 2-blank-line PEP8 spacing the generator
collapsed to 1.
- the shared on-disk cache root moves to a neutral app/plex/cache.py, so
subtitles.py no longer imports it from imgcache.py (drops the cross-import).
- the former plex.py module docstring's access-model note (read endpoints open
to any authed user; admin endpoints test/sync) is restored in the package
__init__.py.
R12 S1 step A. Move the pure, leaf-level helpers out of the 2227-line
routes/plex.py into the app/plex service package with public names:
- app/plex/imgcache.py — on-disk poster/art cache + proxy (was _img_cache_*,
_image_key, _img_response, _IMG_CACHE/_IMG_SIZES). Owns the shared cache dir.
- app/plex/subtitles.py — WebVTT convert/time-shift + subtitle cache (was
_srt_to_vtt, _shift_vtt, _ffmpeg_to_vtt, _sub_cache_*, _BITMAP_SUBS).
- app/plex/rollup.py — show watch-state aggregation (was _rollup,
_show_status, _show_agg_subq, _show_state_map).
Behaviour-equivalent move: bodies verbatim, only the public API renamed and
call sites re-qualified. No endpoint or SQL change (db.query kept as-is; the
2.0 select() conversion is a later step). plex.py 2227 -> 2011 lines.
Gate: ruff clean, pytest 193 passed (pure-logic + DB lane).
peter