Release 3.8.2.11: idle rev-cache, port-safe Connect, single-instance tray UX.

Faster unchanged polls; orphan-core cleanup on listen ports; clearer busy-port errors; cores only from binDir; incremental server list; CSP without Google Fonts; single-instance activates existing window; close-to-tray without kill-others or balloon.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/singleinstance/flock_unix.go

@@ -0,0 +1,16 @@
+//go:build !windows && !plan9
+
+package singleinstance
+
+import (
+	"os"
+	"syscall"
+)
+
+func flockExclusive(f *os.File) error {
+	return syscall.Flock(int(f.Fd()), syscall.LOCK_EX|syscall.LOCK_NB)
+}
+
+func funlock(f *os.File) error {
+	return syscall.Flock(int(f.Fd()), syscall.LOCK_UN)
+}