feat(bland): BTTS ws integration

[rosetta-livekit-bot]

Ports livekit/agents#6752 to the Bland TypeScript plugin.

Summary

• add native realtime text streaming over Bland's /v2/tts/ws endpoint
• pool initialized sessions and preserve cancellation, retry, error, and option-invalidation semantics
• keep HTTP synthesis available, including an HTTP-only streaming: false mode
• default to Bland's River voice and document the new behavior
• add the ws runtime dependency and a minor Bland changeset for the new public streaming API

Validation

• pnpm test plugins/bland/src/tts.test.ts --silent (51 passed, 1 credential-dependent integration skipped)
• pnpm build --filter=@livekit/agents-plugin-bland...
• pnpm lint --filter=@livekit/agents-plugin-bland
• pnpm api:check --filter=@livekit/agents-plugin-bland
• pnpm exec prettier --check "plugins/bland/**/*.{ts,tsx,md,json}" ".changeset/fresh-rivers-stream.md"
• cue-cli voice-mode validation with the built Bland plugin and a local protocol-compatible server: reached AS_SPEAKING, reported Bland TTS usage, committed the assistant message, and returned to AS_LISTENING without an error event

Source diff coverage

Source diff coverage

• livekit-plugins/livekit-plugins-bland/README.md: adapted to plugins/bland/README.md, preserving realtime WebSocket/input-streaming guidance, HTTP-only synthesize() behavior, streaming: false guidance, and the Bland realtime TTS reference in the target README format.
• livekit-plugins/livekit-plugins-bland/livekit/plugins/bland/__init__.py: adapted through plugins/bland/src/index.ts; its existing wildcard export exposes the new public SynthesizeStream, so no redundant index edit was needed.
• livekit-plugins/livekit-plugins-bland/livekit/plugins/bland/tts.py: adapted to plugins/bland/src/tts.ts, including the complete WebSocket protocol, 50-second pooled sessions, 500 ms bounded cancellation drain, retry/error classification, option invalidation, prewarm/close lifecycle, disabled-streaming mode, River default, and preserved HTTP synthesis. Target-required support was added in plugins/bland/package.json, pnpm-lock.yaml, plugins/bland/etc/agents-plugin-bland.api.md, and .changeset/fresh-rivers-stream.md.
• tests/test_plugin_bland_tts.py: adapted to plugins/bland/src/tts.test.ts, porting the source-added and source-modified coverage with Vitest and local WebSocket servers while retaining existing target HTTP coverage.
• Not applicable: none. No source behavior or required infrastructure was omitted.

---

Ported from livekit/agents#6752

Original PR description

• Websocket-based realtime streaming through /v2/tts/ws endpoint
• Proper input streaming (ex. from an LLM text stream) is supported now
• Significant improvements to latency all around

[changeset-bot]

🦋 Changeset detected

Latest commit: ed8a709

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 40 packages

Name	Type
@livekit/agents-plugin-bland	Major
@livekit/agents	Major
@livekit/agents-plugin-anam	Major
@livekit/agents-plugin-anthropic	Major
@livekit/agents-plugin-assemblyai	Major
@livekit/agents-plugin-azure	Major
@livekit/agents-plugin-baseten	Major
@livekit/agents-plugin-bey	Major
@livekit/agents-plugin-cartesia	Major
@livekit/agents-plugin-cerebras	Major
@livekit/agents-plugin-deepgram	Major
@livekit/agents-plugin-did	Major
@livekit/agents-plugin-elevenlabs	Major
@livekit/agents-plugin-fishaudio	Major
@livekit/agents-plugin-google	Major
@livekit/agents-plugin-hedra	Major
@livekit/agents-plugin-hume	Major
@livekit/agents-plugin-inworld	Major
@livekit/agents-plugin-krisp	Major
@livekit/agents-plugin-lemonslice	Major
@livekit/agents-plugin-liveavatar	Major
@livekit/agents-plugin-livekit	Major
@livekit/agents-plugin-minimax	Major
@livekit/agents-plugin-mistral	Major
@livekit/agents-plugin-mistralai	Major
@livekit/agents-plugin-neuphonic	Major
@livekit/agents-plugin-openai	Major
@livekit/agents-plugin-perplexity	Major
@livekit/agents-plugin-phonic	Major
@livekit/agents-plugin-protoface	Major
@livekit/agents-plugin-resemble	Major
@livekit/agents-plugin-rime	Major
@livekit/agents-plugin-runway	Major
@livekit/agents-plugin-sarvam	Major
@livekit/agents-plugin-silero	Major
@livekit/agents-plugin-soniox	Major
@livekit/agents-plugin-tavus	Major
@livekit/agents-plugin-trugen	Major
@livekit/agents-plugin-xai	Major
@livekit/agents-plugins-test	Major

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[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 2 additional findings.