feat(mcp): expose thread organization commands#10554

Note

Add t3_thread_organize MCP tool to dispatch thread organization commands

• Adds the t3_thread_organize tool schema and toolkit, then registers live handlers that map pin, unpin, snooze, unsnooze, settle, unsettle, archive, unarchive, and mark-unread actions to orchestration commands
• Introduces thread-access helpers in threadAccess.ts: caller resolution requires the orchestration capability, thread lookup is scoped to the caller's project, and the active-owner guard rejects archived callers or provider mismatches with parent_not_active\n- Writable-thread validation fails when the target thread's runtime or interaction mode would broaden the caller's mode; missing snoozedUntil returns invalid_request and dispatch failures return the fixed public orchestration_error payload
• Adds tests for schema uniqueness across toolkits, capability denial before the management service is used, storage-failure boundary behavior, and integration pin/unpin plus cross-project thread_not_found
• Refactors turn-request launch error handling in ws.ts into tag-specific mappers for AttachmentClaimError, ThreadLaunchError, and ServerRuntimeStartupError
• Risk: mutation flows now enforce the active-owner guard in assertLiveCaller; any caller lacking an active run or owned by a different provider instance will receive parent_not_active where they previously may have succeeded

^{Macroscope summarized c03cefc.}