docs: list Agent Action Capsule (capsule-emit) in the observability integrations

Feature Area

Documentation

Is your feature request related to an existing bug?

Not a bug. This is a documentation/integration request, opened per the first-time-contributor process to accompany PR #7113.

Describe the solution you'd like

Add a short page to the observability integrations docs for capsule-emit (CapsuleEventListener), an open-source event-bus listener that records each CrewAI step as a signed, content-addressed Agent Action Capsule — audit evidence that a third party can verify offline, complementary to tracing. The listener attaches via CrewAI's standard event bus (no core changes), sealing a planned/executed/failed chain per step.

It sits alongside the other observability vendors already listed (AgentOps, Langfuse, etc.) — same shape: a short page pointing at the integration's own docs. PR #7113 has the page, executed against the released package.

Additional context

Disclosure: the page and this issue were drafted with AI assistance under human review — please apply the llm-generated label (I don't have permission to set it as a first-time contributor). I co-maintain capsule-emit and am engaged by its sponsoring project; that's stated in the PR.

Willingness to contribute

Yes, I'd be happy to submit a pull request (already open as #7113).

Start with PR #7113 and the existing observability integrations pages. Confirm that the capsule-emit page follows the same short-page format and links to the integration's own documentation; done means the integration is listed alongside vendors such as AgentOps and Langfuse.