fix(ft8): restore Look4Sat Pro label/icon, add AppCompat theme

User reported the app installed as "FT8CN" with the FT8CN icon and
FT8 not opening. Root causes (verified by aapt badging on the release
APK):
1. module values/strings.xml carried <string name="app_name">FT8CN
   which won the resource merge -> application-label became FT8CN.
   Removed it; dialogs that referenced R.string.app_name now use a
   module-local ft8cn_app_name (HelpDialog/ClearCacheDataDialog).
2. module shipped its own mipmap ic_launcher* (8 files) which
   overrode our launcher icon -> deleted all of them.
3. MainActivity extends AppCompatActivity but the module's
   <application> lost android:theme when the conflicting attributes
   were stripped -> startup crash. Re-added android:theme=Theme.Ft8CN
   (MaterialComponents) on the module application element.
Verified: processReleaseManifest/Resources + ft8 javac + app kotlin
BUILD SUCCESSFUL. Plan: .hermes/plans/2026-08-05_150000-v455-fix-plan.md

feature/ft8/src/main/AndroidManifest.xml

@@ -19,7 +19,7 @@
     <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
     <uses-permission android:name="android.permission.WAKE_LOCK" />
 
-    <application>
+    <application android:theme="@style/Theme.Ft8CN">
         <activity
             android:name=".grid_tracker.GridTrackerMainActivity"
             android:screenOrientation="sensorLandscape"