fix(overlay): identify Windows mpv windows through IPC PID (#330)

changes/windows-overlay-diagnostics-docs.md

@@ -0,0 +1,4 @@
+type: docs
+area: overlay
+
+- Explain how to collect and interpret Windows overlay attachment and readiness warnings without enabling debug logging.

changes/windows-overlay-pid-attachment.md

@@ -0,0 +1,6 @@
+type: fixed
+area: overlay
+
+- Windows overlay attachment now identifies mpv through its IPC process ID, removing the dependency on PowerShell command-line lookups and allowing the IPC socket to be configured in `mpv.conf`.
+- Revalidate cached Windows mpv process IDs and expire them after sustained IPC failures so PID reuse cannot keep the overlay attached to an unrelated window.
+- Diagnose stalled Windows overlays at the default warn log level, including tracking/PID state, renderer readiness, opacity, native binding errors, and recovery, with repeated warnings rate limited.