Add double/long press, redesign UI to v0.3 with circular d-pad

- Double press and long press detection per button (5 buttons × 3 event
  types = 15 distinct BTHome events)
- New circular d-pad UI: large ring with chevron arrows, numbered buttons
  (1=centre, 2=up, 3=down, 4=left, 5=right) outside/inside the ring
- Bluetooth icon asset (bluetooth_10x10.png) in top-left via canvas_draw_icon
- Back arrow icon (Pin_back_arrow_10x8.png) bottom-right as exit hint
- Version v0.3 bottom-left; direction + event label centred when active
- Thread-safe timer callbacks via view_dispatcher_send_custom_event

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EYNXvRg4xjHHE9oPH9kYYU

application.fam

@@ -5,8 +5,8 @@ App(
     entry_point="bt_home_controller_app",
     stack_size=2 * 1024,
     fap_category="Bluetooth",
-    fap_version="0.1",
-    fap_icon="bthome.png",
+    fap_version="0.3",
+    fap_icon="assets/bluetooth_10x10.png",
     fap_description="BTHome D-pad controller for the Flipper Zero",
     fap_author="Alessandro Ghedini",
     fap_weburl="https://github.com/ghedo/flipper-bthome",