fix(acp): stream agent-initiated turn updates

[bjvgukv25842-cmyk]

Related Issue

Fixes #2163

Problem

The ACP adapter subscribed to SDK events only while a session/prompt request was in flight. Agent-initiated turns triggered by background work, cron, or autonomous continuation therefore continued running but emitted no live session/update notifications after the prompt returned.

What changed

• Keep one SDK event subscription for the lifetime of each ACP session and reuse the existing event-to-ACP mappings for prompt-driven and agent-initiated main-agent turns.
• Track prompt waiters separately so only the matching main-agent turn.ended settles a prompt; autonomous turns and subagent events cannot settle unrelated requests.
• Dispose persistent listeners when sessions are replaced or the ACP transport closes.
• Cover normal prompt streaming, autonomous assistant/thinking/tool/plan updates, subagent filtering, autonomous turn completion, and listener cleanup.
• Add a patch changeset for the user-visible ACP fix.

This intentionally does not add _meta markers, disconnected buffering, or replay of missed history.

Validation:

• corepack pnpm --filter @moonshot-ai/acp-adapter test (328 tests passed)
• corepack pnpm --filter @moonshot-ai/acp-adapter typecheck
• corepack pnpm lint (0 errors)

Checklist

• I have read the CONTRIBUTING document.
• I have linked a related issue, or explained the problem above.
• I have added tests that prove my feature works.
• Ran gen-changesets skill, or this PR needs no changeset.
• Ran gen-docs skill, or this PR needs no doc update.

[changeset-bot]

🦋 Changeset detected

Latest commit: 11c7a83

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

This PR includes changesets to release 1 package

Name	Type
@moonshot-ai/kimi-code	Patch

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