feat(plex): filter the feed by playback class (Direct Play / Direct Stream / Transcode HW/SW)

Adds a movie-scoped "Playback" filter to the Plex feed so a user can isolate items by how
they play — the groundwork for collecting HW-transcodable (or no-transcode) versions.

Four classes derived from the stored `playable` + a new `transcode_hw` facet:
- Direct Play (direct), Direct Stream (remux)
- Transcode · HW  — playable=transcode AND the iGPU can hardware-transcode it
- Transcode · SW  — playable=transcode, software libx264 only

The HW/SW split is precise, not codec-only: a 10-bit/HDR HEVC is HW-decodable yet breaks the
VAAPI nv12 pipeline (the same case plex/stream special-cases), so it must count as SW.

Backend:
- New PlexItem columns (migration 0077): transcode_hw, video_bit_depth, media_probed_at.
  Migration backfills transcode_hw codec-only so the filter works immediately.
- `plex.sync.transcode_hw_capable` is the single classifier; the HW-decodable codec set moves
  to sync as `HW_DECODABLE_CODECS` and plex.stream imports it, so the catalog facet and the
  runtime encoder choice can't disagree by codec.
- Bit-depth backfill (`_probe_media_batch`, wired into sync): probes only HW-decodable transcode
  items' video Stream for bit-depth + HDR and refines a 10-bit/HDR HEVC to software. Bounded
  per run, watermarked by media_probed_at. A codec change resets the watermark (stale probe).
- Filter + self-excluded facet on a shared `playback_class_expr` CASE (movie-leg only — a show
  is an aggregate with no single class). transcode_hw threaded onto the feed/detail/card JSON.

Frontend:
- Multi-select "Playback" Combobox in the sidebar (movie scope, facet-empty drop-out), active
  chips, 4-way corner-dot badge (green/blue/amber/red) + tooltip, and an info-page playback chip
  with a codec · bit-depth subtitle. New `bg-info` (blue) token, i18n HU/EN parity.
- Fix a regression where the card's playback dot lost its hover tooltip: the full-card reveal
  overlay swallowed the cursor; the dot now sits above it (z-20).

Gate: backend full lane + frontend typecheck/lint/knip/prettier/vitest all green. Browser-UAT'd
on localdev (filter narrows to the SW set, facet counts, badge colour + tooltip, info chip).

backend/app/plex/query.py

@@ -9,6 +9,8 @@ from datetime import datetime, timedelta, timezone
 from sqlalchemy import and_, case, func, or_, select, type_coerce
 from sqlalchemy.dialects.postgresql import JSONB
 
+from app.models import PlexItem
+
 TS_CONFIG = "public.unaccent_simple"
 
 # --- Language-aware column pickers (E5 S6) ----------------------------------
@@ -206,6 +208,32 @@ def apply_meta_filters(q, model, p: dict, lang: str = "en"):
     return q.where(*conds) if conds else q
 
 
+# --- Playback-class filter (E7) — MOVIE-ONLY (a show is an aggregate with no single class) ---------
+# The 4 classes the feed filter + facet expose, derived from the stored `playable` + `transcode_hw`.
+# ONE definition (this SQL CASE) so the filter WHERE and the facet counts can't drift: `playable_conds`
+# filters on it, `facets` groups by it. transcode_hw IS NOT True groups NULL (unprobed) with software.
+_PLAYBACK_CLASSES = ("direct", "remux", "transcode_hw", "transcode_sw")
+
+
+def playback_class_expr():
+    """SQL CASE mapping a PlexItem (movie) to its playback-class string, or NULL. The HW branch must
+    precede the generic transcode branch (ordered evaluation)."""
+    return case(
+        (PlexItem.playable == "direct", "direct"),
+        (PlexItem.playable == "remux", "remux"),
+        (and_(PlexItem.playable == "transcode", PlexItem.transcode_hw.is_(True)), "transcode_hw"),
+        (PlexItem.playable == "transcode", "transcode_sw"),
+        else_=None,
+    )
+
+
+def playable_conds(sel: list[str]) -> list:
+    """A one-element condition list (or empty) selecting the given playback classes — an OR via
+    `class IN (...)` over the shared CASE. Unknown keys are dropped."""
+    keep = [c for c in sel if c in _PLAYBACK_CLASSES]
+    return [playback_class_expr().in_(keep)] if keep else []
+
+
 @dataclass
 class LibraryFilters:
     """The shared sidebar filter query-params for /library + /facets, declared once and injected via
@@ -228,6 +256,7 @@ class LibraryFilters:
     keywords: str | None = None  # TMDB keyword chips (E5 S5), CSV; language-neutral
     collections: str | None = None  # CSV of collection rating_keys
     collection_mode: str = "any"  # how multiple collections combine: any (OR, default) | all (AND)
+    playable: str | None = None  # CSV of playback classes: direct|remux|transcode_hw|transcode_sw
 
     def as_dict(self) -> dict:
         return {
@@ -247,6 +276,7 @@ class LibraryFilters:
             "keywords": self.keywords,
             "collections": self.collections,
             "collection_mode": self.collection_mode,
+            "playable": self.playable,
         }