CellGuard app: on-device IMSI-catcher detection (Kotlin/Compose)

- foreground DetectorService: cgcap capture + on-device decode
- framework CellInfo source: real serving+neighbor towers, signal, carrier name
- FrameDecoder: 0x070F cell-info SIT decode
- block-2G/3G + detection toggles via cgctl; libsu root bridge
- silent status notification + edge-triggered alerts

gradle.properties

@@ -0,0 +1,9 @@
+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
+org.gradle.caching=true
+org.gradle.parallel=true
+android.useAndroidX=true
+android.nonTransitiveRClass=true
+kotlin.code.style=official
+# AGP 8.5.2 was validated up to compileSdk 34; silence the (non-fatal) warning
+# for the API 35 compileSdk this project targets.
+android.suppressUnsupportedCompileSdk=35