Reduce idle CPU use and prioritize compositor rendering (#62)

Avoid background title updates when no shell window list is visible, and skip output and capture invalidation for titles outside compositor decorations. Preserve focused titles, fresh window lists and capture privacy.

Request high EGL context priority with fallback, cover rendering and native title behavior in CI, and keep audio recording flowing while video capture is idle.

scripts/tests/test_portal_background_isolated.py

@@ -113,7 +113,9 @@ class BackgroundPortal(unittest.TestCase):
 
                 def snapshot(peer, app):
                     send(peer, {"version": 1, "generation": 0, "last": True, "type": "snapshot", "desktop": {
-                        "outputs": [], "workspaces": [], "windows": [{"id": 1, "app_id": app, "focused": True}],
+                        "outputs": [], "workspaces": [], "windows": [{
+                            "id": 1, "app_id": app, "title": app, "focused": True,
+                            "workspace": 1, "floating": False, "fullscreen": False}],
                         "focus": {"window": 1}, "config": {"revision": 0, "error": None}, "theme": None,
                         "lock": {"phase": "unlocked", "sleeping": False}}})