[draft] Add NVIDIA Riva plugin with STT and TTS support

[toubatbrian]

Description

Ports the NVIDIA Riva STT and TTS plugins from the Python livekit/agents repository to TypeScript for livekit/agents-js. This enables LiveKit Agents to use NVIDIA's Riva speech services for speech recognition and synthesis.

Changes Made

• Added new @livekit/agents-plugin-nvidia package with STT and TTS implementations
• STT: Streaming speech recognition using NVIDIA Riva ASR with interim results and word-level timing
• TTS: Streaming and chunked text-to-speech synthesis using NVIDIA Riva
• Added type definitions for supported models, voices, and languages
• Added NVIDIA_API_KEY to turbo.json globalEnv
• Added changeset for the new plugin
• Added example agent (examples/src/nvidia_agent.ts) demonstrating NVIDIA STT and TTS usage

Pre-Review Checklist

• Build passes: All builds (lint, typecheck, tests) pass locally
• AI-generated code reviewed: Removed unnecessary comments and ensured code quality
• Changes explained: All changes are properly documented and justified above
• Scope appropriate: All changes relate to the PR title
• Video demo: Not applicable - requires NVIDIA API credentials for testing

Testing

• Build passes (pnpm build)
• Lint passes (pnpm lint)
• Automated tests added/updated - No tests added
• Runtime testing with NVIDIA Riva API - Not tested (requires API credentials)

Important Review Notes

⚠️ This implementation has NOT been runtime tested with actual NVIDIA Riva services.

Key areas requiring careful review:

1. gRPC Implementation: The code uses grpc.makeGenericClientConstructor with JSON serialization. Reviewers should verify this approach works with NVIDIA Riva's protobuf-based API, or if proper .proto files need to be used instead.

2. Type Casting: Several as unknown as casts are used for gRPC client types (stt.ts:198, tts.ts:130, tts.ts:290). These work around TypeScript but may hide runtime issues.

3. Default Function IDs: Hardcoded function IDs (1598d209-5e27-4d3c-8079-4751568b1081 for STT, 877104f7-e885-42b9-8de8-f6e4c6303969 for TTS) - verify these are correct/current.

Additional Notes

• Follows existing plugin patterns (deepgram, cartesia, etc.)
• Supports both SSL (cloud) and non-SSL (local NIM) deployments
• SPDX headers added for REUSE compliance
• Package version set to 1.0.0 as initial release

Updates Since Last Revision

• Added SPDX header to README.md to fix REUSE-3.2 compliance check
• Changed changeset from minor to patch
• Set package.json version to 1.0.0
• Added example agent file (examples/src/nvidia_agent.ts) using NVIDIA STT and TTS

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Link to Devin run: https://livekit.devinenterprise.com/sessions/ca0209fd85d4460ebe1eab7ed2be31ea
Requested by: @toubatbrian

Note to reviewers: Please ensure the pre-review checklist is completed before starting your review. Runtime testing with NVIDIA credentials is recommended before merging.

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[changeset-bot]

🦋 Changeset detected

Latest commit: e716065

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

This PR includes changesets to release 18 packages

Name	Type
@livekit/agents-plugin-nvidia	Patch
@livekit/agents	Patch
@livekit/agents-plugin-anam	Patch
@livekit/agents-plugin-baseten	Patch
@livekit/agents-plugin-bey	Patch
@livekit/agents-plugin-cartesia	Patch
@livekit/agents-plugin-deepgram	Patch
@livekit/agents-plugin-elevenlabs	Patch
@livekit/agents-plugin-google	Patch
@livekit/agents-plugin-inworld	Patch
@livekit/agents-plugin-livekit	Patch
@livekit/agents-plugin-neuphonic	Patch
@livekit/agents-plugin-openai	Patch
@livekit/agents-plugin-resemble	Patch
@livekit/agents-plugin-rime	Patch
@livekit/agents-plugin-silero	Patch
@livekit/agents-plugin-xai	Patch
@livekit/agents-plugins-test	Patch

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