Narrow iOS recorder cleanup to session-owned processes

[thymikee]

What to build

Tighten cleanup for simctl recordVideo processes so record stop only signals recorder processes owned by the current session when possible. The current path-based matching is useful as a fallback, but shared temporary paths or similar command lines could collide in edge cases.

Keep the current diagnostics value: failures should still explain what process cleanup attempted.

Acceptance criteria

• Recorder startup records enough ownership metadata to identify the session-owned recorder process.
• Stop cleanup prefers the session-owned PID or parent relationship before falling back to path matching.
• Path-based cleanup remains available as a best-effort fallback with diagnostics.
• Tests cover the narrow match and a collision-like process list where another recorder has a similar output path.
• Existing playable-video validation and stop diagnostics remain intact.

Blocked by

None - can start immediately