Release v3.15.0-beta.1

Merge branch 'feat/webhook-ui' into totaa

Merge feat/mcp-oauth-v3 (squashed MCP OAuth 2.1) into totaa

Merge branch 'feat/image-reference-handling' into totaa

v3.10.0 — TTS expansion: per-provider params, agent override, voice p…

…icker UX

Merge remote-tracking branch 'origin/main' into dev

feat(channels): shared WriterLabel helper with prompt-injection sanit…

…ization

feat(pancake): auto-react allow/deny scope filter + UI toggle

Extends nextlevelbuilder#919 with per-channel scope control for Facebook auto-react.

- AutoReactOptions pointer struct (allow/deny post & user IDs)
- filterAutoReact + containsString helpers; deny overrides allow
- UI surfaces features.auto_react toggle + 4 tags fields
- Nil options = react-all (backward compatible)

feat(pancake): auto-react allow/deny scope filter + UI toggle

Extends nextlevelbuilder#919 with per-channel scope control for Facebook auto-react.

- AutoReactOptions pointer struct (allow/deny post & user IDs)
- filterAutoReact + containsString helpers; deny overrides allow
- UI surfaces features.auto_react toggle + 4 tags fields
- Nil options = react-all (backward compatible)

feat(channels): TTS auto-apply for Discord/Telegram/WhatsApp + UI enh…

…ancements

Backend:
- Add TTS auto-apply support to Discord, Telegram, WhatsApp channels
- Improve text processing for TTS strip markdown
- Wire TTS config handler to gateway server

UI:
- Add voice recorder hook for chat input
- Add agent hooks tab with summary card
- Update i18n for agents (en/vi/zh)
- Minor CSP and credential section fixes