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/singleinstance_other.go

@@ -0,0 +1,36 @@
+//go:build !windows
+
+package singleinstance
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+// Lock uses an exclusive lock file under the user config dir when available.
+func Lock(appName string) (func(), error) {
+	if appName == "" {
+		appName = "Navis"
+	}
+	dir, err := os.UserConfigDir()
+	if err != nil {
+		return func() {}, nil
+	}
+	path := filepath.Join(dir, appName, "singleinstance.lock")
+	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+		return func() {}, nil
+	}
+	f, err := os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0o600)
+	if err != nil {
+		return func() {}, nil
+	}
+	if err := flockExclusive(f); err != nil {
+		_ = f.Close()
+		return nil, fmt.Errorf("%w", ErrAlreadyRunning)
+	}
+	return func() {
+		_ = funlock(f)
+		_ = f.Close()
+	}, nil
+}