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

build.gradle.kts

@@ -0,0 +1,4 @@
+plugins {
+    id("com.android.application") version "8.5.2" apply false
+    id("org.jetbrains.kotlin.android") version "1.9.23" apply false
+}