## Summary
Adds a docs page for LLM observability: every opted-in Vercel AI SDK
call inside a task becomes its own span in the run trace, carrying the
model, provider, token counts, cost, and latency. The page covers
turning it on per call with `experimental_telemetry: { isEnabled: true
}`, what each span inspector tab shows (Overview, Messages, Tools, and a
Prompt tab when linked), linking a call to its prompt version with
`toAISDKTelemetry()`, and querying usage across runs with TRQL against
the `llm_metrics` table.
It sits in the AI dropdown under Features, next to
[Prompts](https://trigger.dev/docs/ai/prompts), and cross-links the
[Query](https://trigger.dev/docs/observability/query) page.
It is explicit that capture is opt-in per call (not automatic) and only
covers Vercel AI SDK calls, and notes the `@ai-sdk/otel` requirement on
AI SDK 7. Every API name, span tab, and TRQL column was checked against
the SDK and the live query schema.
## Also in this PR
Corrects one bullet in the [AI Agents
overview](https://trigger.dev/docs/ai-chat/overview): it claimed an
in-progress chat resumes on the new version after a redeploy, which
contradicts the version-upgrades and backend pages. Chat agent runs are
pinned to the version they started on; moving onto new code is an
explicit version upgrade.
DKP
336f515001