fix(telemetry): close recovered task lifecycles

[IRONICBo]

Summary

• remember tasks that were running when startup recovery marks them interrupted
• emit one recovered socai_agent_task_end event on the next launch
• exclude queued tasks because they never emitted a start event
• document the recovered_on_startup marker

Evidence

The sanitized seven-day Axiom export for v0.5.5 contains two macOS task IDs with one start and no end, plus one Windows task ID with two starts and one end. The persisted task registry already converts leftover running tasks to interrupted at startup, but that recovery path did not emit the matching terminal telemetry event.

This change is prospective. It closes future recovered lifecycles; it cannot backfill historical gaps that were already persisted as interrupted.

Verification

• cargo check -p socai_app
• cargo test -p socai_app tasks::tests::three_tasks_run_while_the_fourth_waits_for_a_released_permit
• git diff --check

[vercel]

@IRONICBo is attempting to deploy a commit to the socai Team on Vercel.

A member of the Team first needs to authorize it.

[IRONICBo]

Closing per maintainer request to keep the active delivery queue focused on four PRs only: audio/video integration, Douyin, TikTok, and the consolidated browser self-healing PR #292. This PR remains available in history and can be restored separately if needed.