Boot splash and periodic announcement banner

Splash: resources/splash/splash.gif built into the binary, played once by
SplashOverlay over a black cover present from the first frame (no UI
flash), then fades into the UI; hides icons loading. GIF, so no
QtMultimedia/gstreamer. Toggle: splash.enabled.

Banner (InfoBanner): metro-style band that fades/slides in with a hold
pictogram; text that does not fit runs as a seamless ticker for two
rounds. Never takes touches; hidden during splash and settings. Config
section banner (enabled, text, intervalSec, showSec, position,
accentColor), editable in the web UI and on-device settings; shown once
after saving.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

webconfig/config_store.py

@@ -49,6 +49,15 @@ def _defaults():
             "pendingColor": "#ffffff",
             "pendingWidth": 6,
         },
+        "banner": {
+            "enabled": False,
+            "text": "Для вызова клининга удерживайте кнопку",
+            "intervalSec": 180,
+            "showSec": 10,
+            "position": "bottom",
+            "accentColor": "#e4002b",
+        },
+        "splash": {"enabled": True},
         "settings": {
             "darkMode": True,
             "password": "admin_26",
@@ -68,7 +77,7 @@ def ensure_defaults(cfg):
     if not isinstance(cfg, dict):
         return base
     cfg.setdefault("version", base["version"])
-    for section in ("layout", "background", "feedback", "settings"):
+    for section in ("layout", "background", "feedback", "banner", "splash", "settings"):
         sec = cfg.setdefault(section, {})
         if not isinstance(sec, dict):
             sec = {}