Route Runtime.enable/disable through the incoming child sessionId instead of always using the tab root session so OOPIF iframe targets receive execution contexts reliably. Add a focused relay regression test for empty-src cross-origin iframe attach flow and update extension version/changelog for release tracking.
- Server rejects new extension (code 4002) if existing has active tabs
- Idle extensions (no tabs) can still be replaced
- Extension properly enters polling mode when rejected during handshake
- /extension/status now returns activeTargets count for smarter reconnection