Add ElevenLabs realtime agents support

[31Carlton7]

What changed

• Added elevenLabs.experimental_realtime() for ElevenAgents WebSocket sessions.
• Added signed URL client-secret creation for agent_id-based conversations.
• Added ElevenAgents event mapping for text, audio, transcripts, tool calls, ping/pong, interruptions, and response completion.
• Added ElevenLabs realtime session options for conversation overrides, dynamic variables, and custom LLM body fields.
• Extended the existing shared Next.js realtime example with ElevenLabs, using the agent-configured prompt, voice, and turn detection.
• Added provider docs and a changeset.

Why

ElevenLabs has realtime agent conversations, but its WebSocket protocol differs from the existing OpenAI/Google/xAI realtime protocol. This adapter normalizes ElevenAgents into the AI SDK realtime interface while preserving ElevenLabs-specific session overrides.

Validation

• pnpm --filter @ai-sdk/elevenlabs type-check
• pnpm --filter @ai-sdk/elevenlabs test:node (38 tests)
• pnpm --filter @ai-sdk/elevenlabs test:edge (38 tests)
• pnpm lint-staged
• Live example connection through /api/realtime/setup, including signed URL creation, WebSocket session, text response, audio events, interruption, and ping/pong
• Browser verification of the shared provider selector, agent defaults, connection lifecycle, transcript, and event log
• git diff --check

Follow-up

AI Gateway wiring is intentionally separate. Gateway can reuse the new exported realtime model/mapper after this package is available, rather than duplicating the ElevenAgents protocol translation.

[gr2m]

compare #15747. Tools work differently with Elevenlabs, if I recall correctly they need to be registered ahead of time, I wanted to investigate further if there is another way. Did the e2e Elevenalbs example work for you out of the box for you?