Release 2.7.3.1: harden proxy recovery, updates and local API.

Restore orphaned system proxy after crash, require update SHA-256, add macOS /api auth token, fix UDP ping false positives, HTTPS-only subscriptions, and keep the UI responsive during connect.

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

internal/sysproxy/sentinel.go

@@ -0,0 +1,39 @@
+package sysproxy
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// SentinelPath is written while Navis owns the OS system proxy.
+// Survives crash/kill so the next launch can clear a stuck proxy.
+func SentinelPath(cfgPath string) string {
+	dir := filepath.Dir(strings.TrimSpace(cfgPath))
+	if dir == "" || dir == "." {
+		dir, _ = os.UserConfigDir()
+		if dir == "" {
+			dir = os.TempDir()
+		}
+		dir = filepath.Join(dir, "Navis")
+	}
+	return filepath.Join(dir, ".navis-proxy-on")
+}
+
+// WriteSentinel marks that system proxy was enabled by Navis.
+func WriteSentinel(cfgPath, httpHostPort string) {
+	path := SentinelPath(cfgPath)
+	_ = os.MkdirAll(filepath.Dir(path), 0o755)
+	_ = os.WriteFile(path, []byte(strings.TrimSpace(httpHostPort)+"\n"), 0o600)
+}
+
+// ClearSentinel removes the ownership marker after a clean Disable.
+func ClearSentinel(cfgPath string) {
+	_ = os.Remove(SentinelPath(cfgPath))
+}
+
+// HasSentinel reports whether a previous session left the proxy marked on.
+func HasSentinel(cfgPath string) bool {
+	_, err := os.Stat(SentinelPath(cfgPath))
+	return err == nil
+}