Add BLE GATT Fuzzer app

Connects, walks every service/characteristic, reads all readable values, and (on OK) writes boundary payloads to writable characteristics, logging every response. For authorised testing. Reuses libble.

ble_gattfuzz/application.fam

@@ -0,0 +1,15 @@
+# Needs firmware from ../build.sh (full BLE stack). Staged with libble/.
+App(
+    appid="ble_gattfuzz",
+    name="BLE GATT Fuzzer",
+    apptype=FlipperAppType.EXTERNAL,
+    entry_point="ble_gattfuzz_app",
+    requires=["gui", "storage"],
+    stack_size=4 * 1024,
+    fap_category="Bluetooth",
+    fap_icon="icon.png",
+    fap_version="1.0",
+    fap_description="Enumerate, read and fuzz a peripheral's GATT database, logging responses",
+    fap_author="andydixon",
+    fap_weburl="https://github.com/andydixon/flipper-bt-inspector",
+)