feat(web): progress subscriber + useProgress hook

feat(web): generateDialog client with per-speaker multipart

feat(web): IndexedDB v2 migration; show seed and reuse button on history rows

feat(web): ParamsPanel splits params into basic + advanced disclosure

chore(api,web): include validation message and detail in /api/generate error response

fix: re-encode reference voices as PCM WAV in browser; expand turbo tag list to 9

feat(web): API client, IndexedDB store, Recorder state machine

feat(web): Vite/React/TS/Tailwind/shadcn scaffold + Studio shell