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>

README.md

@@ -21,6 +21,11 @@ companion Flask web configurator. Both share a single JSON config file.
 - Ethernet configuration via NetworkManager (`nmcli`) from the web UI
 - OTA software update with automatic rollback on a failed launch (health-check)
 - Hot reload: app picks up config changes via `QFileSystemWatcher`
+- Boot splash (`resources/splash/splash.gif`, built into the binary, played once
+  by `qml/SplashOverlay.qml`; covers icons loading). GIF, not mp4: no QtMultimedia
+- Periodic announcement banner (`qml/InfoBanner.qml`, metro-style fade/slide,
+  ticker scroll for long text, never takes touches); text, period, duration,
+  position and colour in the web UI («Внешний вид») and on-device settings
 
 ## Layout
 
@@ -342,6 +347,15 @@ sudo -u buttontask sudo -n /opt/buttontask/scripts/bt-brightness status
     "errorWidth": 6,         // ring width (px) on error
     "glowRadius": 20         // glow radius (0 disables the glow)
   },
+  "banner": {               // periodic announcement over the buttons
+    "enabled": false,
+    "text": "Для вызова клининга удерживайте кнопку",
+    "intervalSec": 180,      // 30..3600, period between shows
+    "showSec": 10,           // 3..60, longer if the text has to scroll
+    "position": "bottom",    // "bottom" | "top"
+    "accentColor": "#e4002b" // stripe + hold-ring colour
+  },
+  "splash": { "enabled": true },   // boot splash, read at app start
   "settings": {
     "darkMode": true,
     "password": "admin",     // shared with web auth