Revive yaris-obd: USB OBD adapter, real GPS/GNSS, offline map, hotspot, SQLite logging, dashcam retrieval

Squashed rewrite of the project revival work (replaces prior history on this
branch to remove personal data that had been accidentally committed - real
LAN IP, GPS coordinates, home WiFi SSID, and phone model). See PLAN.md for
full phase-by-phase details. Summary:

- Phase 2: adapt app_obd.py for a USB OBD-II adapter (was Bluetooth-only),
  auto-detect /dev/ttyUSB*, fix several pre-existing crash bugs.
- Phase 3/4: make the web UI work fully offline (vendored Socket.IO/Leaflet/
  Chart.js/FontAwesome, offline map tile downloader script, live GPS marker
  tracking fix).
- Phase 5: systemd deployment/autostart on the Pi.
- Phase 6: WiFi hotspot mode via NetworkManager (auto-switch between home
  WiFi and a local AP for in-car web UI access), mDNS hostname + port 80
  redirect so the UI is reachable at a plain hostname with no port number.
- Phase 7: fix app_db.py/app_sql.py bugs, wire up local SQLite trip logging.
- Phase 8: brand-agnostic USB dashcam file retrieval (lsblk transport-based
  detection, works with any dashcam brand/folder layout).
- Rewritten readme.md with a proper project overview.

Co-authored-by: Copilot <[email protected]>

modules/app_events.py

@@ -5,6 +5,7 @@ import time, threading
 
 socketio = SocketIO()
 uptime_lock = threading.Lock()
+thread_uptime = None
 
 @socketio.on('connect')
 def connect_event():
@@ -14,9 +15,15 @@ def connect_event():
     uptime()
 
 def uptime():
-    thread = Thread(target=loop_uptime)
-    thread.daemon = True
-    thread.start()
+    global thread_uptime 
+
+    if thread_uptime is None or not thread_uptime.is_alive():
+        thread_uptime = Thread(target=loop_uptime)
+        thread_uptime.daemon = True
+        thread_uptime.start()
+        print(f"Uptime thread started, alive: {thread_uptime.is_alive()}")
+    else:
+        print(f"Uptime thread already running, alive: {thread_uptime.is_alive()}")
 
 def loop_uptime():
     uptime_lock.acquire()