feat(android): foreground-app automation condition

Make the existing Application automation rule (foreground app -> activate
scene) work on the Android-TV build. A Kotlin ForegroundAppBridge reads the
foreground app via UsageStatsManager and lists launchable apps via LauncherApps;
PlatformDetector bridges it in (ahead of the Windows-only ctypes guard) so the
existing AutomationEngine / ApplicationRule / storage / deactivation modes are
unchanged. New /system/installed-apps + /system/info endpoints feed an app picker
that stores package names (vs process names on desktop); on Android the editor
hides the match-type selector since the foreground app is the only obtainable
signal. PACKAGE_USAGE_STATS is granted via an on-device button + a web-UI banner
(no blanket prompt at capture start); detection degrades gracefully until granted.

Zero new Python/Gradle deps (UsageStatsManager + LauncherApps are in-platform;
matching only string-compares the package name, so no QUERY_ALL_PACKAGES).
assembleDebug + 1897 pytest + ruff + tsc + npm build all green; independent final
review (0 blockers) + security review (no critical issues).

android/app/src/main/res/layout/activity_main.xml

@@ -81,6 +81,21 @@
             android:focusableInTouchMode="true"
             android:visibility="gone" />
 
+        <!-- Shown only while Usage Access is missing (needed by the foreground-app
+             automation rule). Like the grant-notification button, its D-pad focus
+             chain is wired at runtime (wireStoppedFocusChain). -->
+        <Button
+            android:id="@+id/grant_usage_access_button"
+            style="@style/Widget.LedGrab.Button.Secondary"
+            android:layout_width="320dp"
+            android:layout_height="56dp"
+            android:layout_marginTop="20dp"
+            android:text="@string/btn_grant_usage_access"
+            android:textSize="18sp"
+            android:focusable="true"
+            android:focusableInTouchMode="true"
+            android:visibility="gone" />
+
         <CheckBox
             android:id="@+id/autostart_check"
             android:layout_width="wrap_content"

android/app/src/main/res/values-ru/strings.xml

@@ -27,4 +27,5 @@
     <string name="notification_text">Веб-интерфейс: %1$s</string>
     <string name="notification_listener_label">Захват уведомлений LedGrab</string>
     <string name="btn_grant_notification_access">Разрешить доступ к уведомлениям</string>
+    <string name="btn_grant_usage_access">Разрешить доступ к статистике использования</string>
 </resources>

android/app/src/main/res/values-zh/strings.xml

@@ -27,4 +27,5 @@
     <string name="notification_text">Web界面:%1$s</string>
     <string name="notification_listener_label">LedGrab 通知捕获</string>
     <string name="btn_grant_notification_access">授予通知访问权限</string>
+    <string name="btn_grant_usage_access">授予使用情况访问权限</string>
 </resources>

android/app/src/main/res/values/strings.xml

@@ -27,4 +27,5 @@
     <string name="notification_text">Web UI: %1$s</string>
     <string name="notification_listener_label">LedGrab notification capture</string>
     <string name="btn_grant_notification_access">Grant notification access</string>
+    <string name="btn_grant_usage_access">Grant usage access</string>
 </resources>