Add BLE Tracker Detector app

Passively scans and flags item trackers by advertising signature (Apple Find My/AirTag, Tile, Samsung SmartTag), with a following-you warning for a tracker seen persistently. Read-only; reuses libble.

ble_tracker/application.fam

@@ -0,0 +1,15 @@
+# Needs firmware from ../build.sh (full BLE stack). Staged with libble/.
+App(
+    appid="ble_tracker",
+    name="BLE Tracker Detector",
+    apptype=FlipperAppType.EXTERNAL,
+    entry_point="ble_tracker_app",
+    requires=["gui", "storage"],
+    stack_size=4 * 1024,
+    fap_category="Bluetooth",
+    fap_icon="icon.png",
+    fap_version="1.0",
+    fap_description="Detect nearby item trackers (AirTag, Tile, SmartTag) and following alerts",
+    fap_author="andydixon",
+    fap_weburl="https://github.com/andydixon/flipper-bt-inspector",
+)