feat(web): info icon on every param with hover/click tooltip; add help text to all params

feat(models): expand chatterbox-mtl params (seed, repetition_penalty, min_p, top_p)

feat(models): expand chatterbox-turbo params (seed, top_k, exaggeration, cfg_weight, etc.)

feat(models): expand chatterbox-en params (seed, repetition_penalty, min_p, top_p)

feat(api): adapter generate returns seed_used; expose X-Seed-Used header

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

feat(models): chatterbox-turbo and chatterbox-mtl adapters

feat(api,models): FastAPI app with /api/health, /api/models, activate, /api/generate + chatterbox-en adapter

feat(models): ModelAdapter protocol + is_valid_adapter check

chore: scaffold python project (requirements, gitignore, pytest, package skeleton)