processes/subtitles: STYLE.md — USER-G style for picks + display

Codifies the bar every fetch must hit:
- one plain English .srt per episode, named <base>.eng.srt
- drop SDH / HearingImpaired / MachineTranslated / AiTranslated / Forced
- prefer fps-matched, then highest download count
- UI label collapsed to just "English" via web-overrides shim

README.md now points at STYLE.md as a hard prereq before any fetch run.
The picker logic in v1/v2/v3 helpers already encodes these rules; STYLE.md
is the canonical source of truth that they should be checked against if
anyone (or future-me) is tempted to relax them.

processes/subtitles/README.md

@@ -8,6 +8,12 @@ command, what to verify, and what to do on failure. Background reference for
 how Jellyfin and the OpenSubtitles plugin work together lives in
 [`docs/03-subtitles.md`](../../docs/03-subtitles.md).
 
+> **Read [`STYLE.md`](STYLE.md) first.** Every fetch must hit the
+> bar set there: one English `.srt` per episode, plain (no SDH / no MT / no
+> AI / no Forced), best-quality release. The picker logic in v1/v2/v3
+> mirrors that bar; if a step would violate it, stop and ask before
+> downloading.
+
 ---
 
 ## Prereqs (verify before running)

processes/subtitles/STYLE.md

@@ -0,0 +1,73 @@
+# Subtitle USER-G style — ARRFLIX
+
+The bar every fetch should hit. If a recipe step would violate any of these,
+stop and ask before proceeding.
+
+## 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.
+
+## What gets picked
+
+In order:
+
+1. **English** language — `eng` / `en`. Never auto-pick `en-US`/`en-GB`
+   variants over plain `en`; treat them equivalent for matching.
+2. **No SDH / Hearing Impaired** — drop any sub flagged `hearing_impaired`,
+   `sdh`, `cc`. Only fall back to SDH if no plain-English option exists.
+3. **No machine / AI translation** — drop `machine_translated`,
+   `ai_translated`. Hand-authored subs only.
+4. **No forced subtitles** — drop `foreign_parts_only` / `Forced` unless the
+   episode has English audio with foreign-language scenes that need
+   translation (rare for US shows).
+5. **Frame-rate match** — prefer entries whose declared fps matches the
+   source video (typically 23.976 for our masters). Treat `0.0` as unknown
+   and fall through to step 6.
+6. **Highest download count** within the surviving candidates — proxies for
+   "the version everyone agreed was best."
+
+After fetch, **eyeball-verify one sample episode per show** plays in sync
+(±1 s on a known dialogue line) before declaring the show done.
+
+## What doesn't ship
+
+- Multiple language tracks per episode (no German/French alternatives —
+  English-only library).
+- 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.
+
+## How the UI presents subs
+
+The detail-page subtitle dropdown is shimmed via
+`web-overrides/index.html` (markers `SUB-LABEL-SHIM-BEGIN/END`). Stock
+Jellyfin shows e.g. `English - SUBRIP - External - Default`; the shim
+collapses to `English`, with `(Forced)` / `(SDH)` / `(Hearing Impaired)`
+suffixes only when those flags actually apply. `Default` is dropped — it's
+redundant when there's only one stream per language.
+
+Revert: `bin/revert-sub-label-shim.sh`.
+
+## Why these rules
+
+- Boutique-release-group quality bar from
+  [`README.md`](../../README.md): "every show and film is the best version
+  I could put together."
+- 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
+  and not what someone reaches for unless they specifically need it.
+- Machine / AI translations are inconsistent and often wrong on slang or
+  show-specific terms (esp. animated comedies).
+- Frame-rate-matched subs sync without manual offset on first try; mismatch
+  generally still works on NTSC (29.97 vs 23.976 are the same elapsed time)
+  but hash-match or fps-match removes that gamble.