subs: add source-priority tier ladder, accept original-release bitmap as tier 2

Original-release bitmap subs (PGS, VobSub, dvd_subtitle) are first-class,
not stop-gaps. They're the canonical studio render — bitmap encoding is
just a format choice, not a quality compromise. OCR'd or AI-rebuilt
sidecars introduce transcription error that the source doesn't have.

STYLE.md changes:
- New "Source priority" section with 4 tiers: original text > original
  bitmap > trusted text rips > WhisperX rebuild.
- "What lands on disk" loosened: at least one English stream (embedded
  OR sidecar), keep embedded codec as-is, sidecar still .srt.
- New "OCR bitmap -> text" section documenting pgsrip recipe as an
  optional UX-nicety augmentation, not a correctness fix.
- "Why these rules" now explains why original > pretty (esp. for older
  shows like Futurama S1-3 / early Archer where the master is the only
  authoritative source and upscale artifacts already dominate).

STOPGAP-SUBS.md: header note clarifying bitmap-from-disc is NOT a
stop-gap; lists Lilo & Stitch (2002) and Archer (2009) S02 as examples
of correct-as-shipped library entries.

playbooks/subtitles/STOPGAP-SUBS.md

@@ -6,6 +6,16 @@ v4 WhisperX (ROADMAP H5) lands on the friend RTX 4080 node, **regenerate
 every show on this list** with proper-noun-prompted transcription and
 replace the sidecars in place. Keep this file as the v4 worklist.
 
+**NOT a stop-gap** (do NOT log here): embedded original-release bitmap
+subs (PGS, VobSub, `dvd_subtitle`). Per [`STYLE.md`](STYLE.md) tier 2,
+those are first-class — they're the original studio render and ship
+as-is. Examples currently in library that are correct, not stop-gap:
+- Lilo & Stitch (2002) — 2× embedded English PGS
+- Archer (2009) S02 — 3× embedded DVD-bitmap (eng/spa/fre)
+
+Optional `pgsrip` OCR sidecar for those is a UX nicety, not a
+correctness fix — see STYLE.md "OCR bitmap → text".
+
 ## Active stop-gaps
 
 | Show | Eps subbed | Source path | Why stop-gap | Owner verdict | Logged |

playbooks/subtitles/STYLE.md

@@ -3,17 +3,41 @@
 The bar every fetch should hit. If a recipe step would violate any of these,
 stop and ask before proceeding.
 
+## Source priority (highest → lowest)
+
+Accuracy beats format. Use this tier ladder before reaching for OCR/AI:
+
+1. **Original release text subs** (`.srt`/`.ass` from disc/streamer rip,
+   embedded or sidecar). Ground truth — ship as-is.
+2. **Original release bitmap subs** (PGS, VobSub, `dvd_subtitle`,
+   embedded). **Acceptable in their native form** — they ARE the original
+   words from the source master, just rendered as images. Jellyfin server
+   burns them in for clients that can't render natively. Optionally
+   OCR-extract a `.srt` sidecar alongside (do NOT replace the embedded
+   stream) when client-side styling, search, or mobile rendering matters.
+3. **Trusted text rips** from OpenSubtitles (verified uploads, hash-match
+   or high-download-count + frame-rate-match).
+4. **WhisperX rebuild** with `--initial_prompt` proper-nouns yaml — only
+   when no original exists (e.g. user-uploaded YT content with auto-CC).
+   Logged in [`STOPGAP-SUBS.md`](STOPGAP-SUBS.md) until cleared.
+
+Tier 1 and 2 are first-class. Tier 3 is a fallback. Tier 4 is a stop-gap.
+
 ## What lands on disk
 
-- **Exactly one** English subtitle file per episode.
-- Filename: `<videobasename>.eng.srt` — no language-region tags (`en-US`),
-  no flag stack on regular subs (no `.sdh`, no `.forced`, no `.cc` unless
-  there genuinely is no plain-English option).
-- Format: `.srt` (SubRip text). Skip `.ass`, `.ssa`, `.vtt`, `.sup`, `.idx`
-  unless the source has nothing else; convert with `ffmpeg -map 0:s:0 -c:s srt`
-  in that case.
-- Encoding: UTF-8. Re-encode with `iconv` if a sidecar comes back as cp1252
-  / windows-1250.
+- **At least one** English subtitle stream per episode (embedded OR
+  sidecar — not both required).
+- Sidecar filename when used: `<videobasename>.eng.srt` — no
+  language-region tags (`en-US`), no flag stack on regular subs (no
+  `.sdh`, no `.forced`, no `.cc` unless there genuinely is no
+  plain-English option).
+- Sidecar format: `.srt` (SubRip text). For embedded: keep the original
+  codec (`subrip`, `ass`, `pgs`, `vobsub`, `dvd_subtitle`) — do NOT
+  re-mux just to convert format. Convert only when extracting to disk:
+  text codecs via `ffmpeg -map 0:s:0 -c:s srt`, bitmap codecs via OCR
+  (see "OCR bitmap → text" below).
+- Encoding (sidecar): UTF-8. Re-encode with `iconv` if a sidecar comes
+  back as cp1252 / windows-1250.
 
 ## What gets picked
 
@@ -40,12 +64,41 @@ After fetch, **eyeball-verify one sample episode per show** plays in sync
 ## What doesn't ship
 
 - Multiple language tracks per episode (no German/French alternatives —
-  English-only library).
+  English-only library). Drop non-English embedded streams via
+  `mkvpropedit` only if user complains about client picker clutter; do
+  NOT silently strip them on import.
 - Director's commentary, behind-the-scenes, song-only subs.
 - Subs that cover only a partial runtime (the partial-cover heuristic isn't
   scripted yet; spot-check duration vs episode runtime if a srt looks short).
 - "All-episodes-in-one" mega-packs treated as a single episode's sidecar.
 
+## OCR bitmap → text (optional, tier-2 augmentation)
+
+Embedded PGS/VobSub/`dvd_subtitle` are acceptable as-is (tier 2). OCR
+becomes worthwhile when: (a) client repeatedly transcodes due to bitmap
+burn-in (CPU pressure on nullstone — no GPU transcode available), (b)
+user wants to restyle font/size on a specific show, (c) mobile client
+renders bitmap subs poorly.
+
+Recipe (`pgsrip`, batch-friendly, Tesseract-backed):
+
+```bash
+pip install pgsrip
+# PGS: extract embedded to .sup
+ffmpeg -i input.mkv -map 0:s:0 -c copy subs.sup
+pgsrip --language eng subs.sup        # -> subs.srt
+
+# VobSub/dvd_subtitle: extract to .idx + .sub
+mkvextract input.mkv tracks 2:subs.idx
+pgsrip subs.idx                       # -> subs.srt
+```
+
+OCR accuracy ~90–95 % raw, ~95–98 % after Subtitle Edit cleanup. Source
+words are correct (it's transcription of original render, not Whisper
+hallucination) — only font recognition fights you. Resulting `.srt`
+ships as sidecar **alongside** the embedded bitmap stream, not as a
+replacement.
+
 ## How the UI presents subs
 
 The detail-page subtitle dropdown is shimmed via
@@ -62,6 +115,14 @@ Revert: `bin/revert-sub-label-shim.sh`.
 - Boutique-release-group quality bar from
   [`README.md`](../../README.md): "every show and film is the best version
   I could put together."
+- **Original-release subs > pretty format.** The DVD/BD/streamer master
+  is the canonical script — bitmap or text, those are the words the
+  studio shipped. An OCR'd or AI-rebuilt sidecar is a derivative that
+  introduces error (font confusion, mistranscription); the original
+  doesn't. Especially true for older shows (Futurama S1–S3, Archer
+  early seasons) where the master is the only authoritative source and
+  upscale artifacts already dominate the visual experience — bitmap
+  subs match the source vibe.
 - One-language library = one stream per ep = no need to expose codec or
   source in UI.
 - SDH/CC adds `[door slams]`, `[music]` etc. — distracting on first watch