refactor(huddle): switch local TTS to Pocket TTS (Kyutai/sherpa-onnx)

desktop/scripts/check-file-sizes.mjs

@@ -66,13 +66,13 @@ const overrides = new Map([
   ["src/features/settings/ui/ChannelTemplatesSettingsCard.tsx", 850], // template CRUD card + TemplateFormDialog (persona/team chip selectors + provider assignments + canvas template) + TemplateTeamSelector + ProviderAssignments + ProviderRow
   ["src/shared/api/types.ts", 620], // ... + RespondToMode + respondTo/respondToAllowlist on ManagedAgent/Create/Update inputs
   ["src-tauri/src/events.rs", 610], // event builders + build_huddle_guidelines (kind:48106) + post_event_raw transport helper + participant p-tag on join/leave + NIP-43 relay admin builders (add/remove/change-role) + check_relay_role + DM/presence/workflow command builders
-  ["src-tauri/src/huddle/kokoro.rs", 980], // Kokoro ONNX TTS engine + three-tier G2P + ARPAbet→IPA + CoreML + synth_chunk() public API + style validation + hyphenated compound splitting + 23 unit tests
   ["src-tauri/src/huddle/mod.rs", 1020], // huddle state machine + Tauri commands + sync protocol doc; state/relay/pipeline extracted + emit_huddle_state_changed wiring
-  ["src-tauri/src/huddle/models.rs", 900], // model download manager for Parakeet TDT-CTC STT + Kokoro TTS with streaming downloads + SHA-256 verification + Rust-native tar extraction + version manifest + atomic swap + hot-start signaling + CC-BY-4.0 attribution sidecar + idempotent legacy Moonshine dir cleanup
+  ["src-tauri/src/huddle/models.rs", 950], // model download manager for Parakeet TDT-CTC STT + Pocket TTS with streaming downloads + SHA-256 verification + Rust-native tar extraction + version manifest + atomic swap + hot-start signaling + MODEL_LICENSE.txt sidecar (fail-closed readiness) + idempotent legacy Moonshine dir cleanup + tts_readiness_requires_license_sidecar test + Mary (VCTK p333) reference voice attribution block
   ["src-tauri/src/huddle/stt.rs", 580], // STT pipeline + PTT edge-detection flush + PTT gating (is_speech AND ptt_active) + barge-in for VAD mode + rubato resampler + earshot VAD + sherpa-onnx transcription
+  ["src-tauri/src/huddle/pocket.rs", 900], // Pocket TTS engine wrapper + prepare_pocket_prompt (capitalize/punctuate/pad short inputs + insert ". . " sacrificial cold-start prefix, mirror upstream pocket-tts prepare_text_prompt) + build_generation_extra (only overrides max_frames, and only for ≤4-word inputs, to bound runaway "monster breathing" generation without clipping multi-clause sentences) + trim_leading_cold_start (post-synth strip of sacrificial audio on short prompts, workaround for kyutai-labs/pocket-tts #91 first-phoneme drop) + 18 unit tests including regressions for the static-burst-on-multi-clause-sentence bug and the first-phoneme-drop trim hazards
   ["src-tauri/src/huddle/preprocessing.rs", 670], // TTS text preprocessing pipeline + unified split_sentences + int_to_words 0-999999 + URL trailing punctuation preservation + 23 unit tests
   ["src-tauri/src/huddle/relay_api.rs", 520], // audio relay recv task + per-peer frame counting for remote human TTS interrupt + NIP-98 channel member query
-  ["src-tauri/src/huddle/tts.rs", 1030], // TTS pipeline + session warmup + cancel/shutdown handling + apply_fades + 18 unit tests for remote interrupt mechanism
+  ["src-tauri/src/huddle/tts.rs", 1380], // TTS pipeline + session warmup + cancel/shutdown handling + apply_fade_out (fade-out only — leading fade removed 2026-05-18 after onset-attenuation regression measured in examples/pocket_onset_probe.rs) + FIRST_APPEND_LEAD_IN_SAMPLES + build_sentence_append_plan (pure helper enforcing the lead-in fires exactly once per utterance, not per sentence — see lead_in_pad_fires_exactly_once_per_utterance regression test) + normalize_for_playback (per-sentence peak normalization to -3 dBFS ceiling with MAX_GAIN cap) + 30 unit tests (18 interrupt + 5 fade-out + 1 first-append-lead-in + 3 build-sentence-append-plan + 6 normalize)
   ["src-tauri/src/relay.rs", 510], // +4 lines for NIP-OA auth tag injection in profile sync (build_profile_event) + verification test
   ["src-tauri/src/commands/pairing.rs", 600], // NIP-AB pairing actor: 3 Tauri commands + background WS task + NIP-42 auth + NIP-43 probe + event parsing helpers
   ["src-tauri/src/lib.rs", 715], // +4 lines for PairingHandle managed state + 3 pairing command registrations