Qualify regional disc browsing

[pxdl]

Summary

• pin the vendored extractor to ae3-sdk 5b2207e3580ae4cc1d588641f4fe3f898350e501
• isolate malformed image/FMV assets while keeping operational failures fatal
• bind persisted catalogs and payloads to disc and content identity
• make disc opening, teardown, worker messages, cache fallback, and ZIP export fail closed
• document the measured regional support matrix

Qualification

• Japanese demo PCPX_966.57: 3,518 textures / 3,527 pictures; the declared-TM2 placeholder is isolated and 01_00.tm2 decodes at 256×256 IDTEX8
• Korean retail SCKA_200.62: 101 Effects banks; boss_specter exposes 97 groups / 30 requests
• PAL retail SCES_536.42: 22/22 FMVs; new_play01 reaches Ended at 512×512 with stereo 48 kHz PS-ADPCM and TFF bob output at 59.94 Hz
• US retail SCUS_975.01: 11,931 textures / 11,950 pictures, 101 Effects banks, and 22/22 FMVs; new_play01 reaches Ended at 512×448
• cross-disc catalog and source attachment probes are rejected before reuse

The detailed evidence record remains private and contains no disc payloads, screenshots, or cache values.

Verification

• npm test — 105/105 passed from a clean worktree
• npm run typecheck — passed from a clean worktree
• npm run build — passed from a clean worktree; only the existing 500 kB model-browser chunk warning remains
• browser smoke: Images, Effects, FMV cataloging/playback, and source switching across all four measured discs

Closes #4