Merge upstream/main and resolve acars, vdl2, dashboard conflicts

Resolved conflicts:
- routes/acars.py: keep /messages and /clear endpoints for history reload
- routes/vdl2.py: keep /messages and /clear endpoints for history reload
- templates/adsb_dashboard.html: keep removal of hardcoded device-1
  defaults for ACARS/VDL2 selectors (users pick their own device)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

routes/adsb.py

@@ -72,6 +72,7 @@ adsb_last_message_time = None
 adsb_bytes_received = 0
 adsb_lines_received = 0
 adsb_active_device = None  # Track which device index is being used
+adsb_active_sdr_type: str | None = None
 _sbs_error_logged = False  # Suppress repeated connection error logs
 
 # Track ICAOs already looked up in aircraft database (avoid repeated lookups)
@@ -674,7 +675,7 @@ def adsb_session():
 @adsb_bp.route('/start', methods=['POST'])
 def start_adsb():
     """Start ADS-B tracking."""
-    global adsb_using_service, adsb_active_device
+    global adsb_using_service, adsb_active_device, adsb_active_sdr_type
 
     with app_module.adsb_lock:
         if adsb_using_service:
@@ -757,6 +758,7 @@ def start_adsb():
         sdr_type = SDRType(sdr_type_str)
     except ValueError:
         sdr_type = SDRType.RTL_SDR
+        sdr_type_str = sdr_type.value
 
     # For RTL-SDR, use dump1090. For other hardware, need readsb with SoapySDR
     if sdr_type == SDRType.RTL_SDR:
@@ -787,7 +789,7 @@ def start_adsb():
 
     # Check if device is available before starting local dump1090
     device_int = int(device)
-    error = app_module.claim_sdr_device(device_int, 'adsb')
+    error = app_module.claim_sdr_device(device_int, 'adsb', sdr_type_str)
     if error:
         return jsonify({
             'status': 'error',
@@ -795,6 +797,10 @@ def start_adsb():
             'message': error
         }), 409
 
+    # Track claimed device immediately so stop_adsb() can always release it
+    adsb_active_device = device
+    adsb_active_sdr_type = sdr_type_str
+
     # Create device object and build command via abstraction layer
     sdr_device = SDRFactory.create_default_device(sdr_type, index=device)
     builder = SDRFactory.get_builder(sdr_type)
@@ -821,11 +827,24 @@ def start_adsb():
         )
         write_dump1090_pid(app_module.adsb_process.pid)
 
-        time.sleep(DUMP1090_START_WAIT)
+        # Poll for dump1090 readiness instead of blind sleep
+        dump1090_ready = False
+        poll_interval = 0.1
+        elapsed = 0.0
+        while elapsed < DUMP1090_START_WAIT:
+            if app_module.adsb_process.poll() is not None:
+                break  # Process exited early — handle below
+            if check_dump1090_service():
+                dump1090_ready = True
+                break
+            time.sleep(poll_interval)
+            elapsed += poll_interval
 
         if app_module.adsb_process.poll() is not None:
             # Process exited - release device and get error message
-            app_module.release_sdr_device(device_int)
+            app_module.release_sdr_device(device_int, sdr_type_str)
+            adsb_active_device = None
+            adsb_active_sdr_type = None
             stderr_output = ''
             if app_module.adsb_process.stderr:
                 try:
@@ -871,7 +890,6 @@ def start_adsb():
             })
 
         adsb_using_service = True
-        adsb_active_device = device  # Track which device is being used
         thread = threading.Thread(target=parse_sbs_stream, args=(f'localhost:{ADSB_SBS_PORT}',), daemon=True)
         thread.start()
 
@@ -891,14 +909,16 @@ def start_adsb():
         })
     except Exception as e:
         # Release device on failure
-        app_module.release_sdr_device(device_int)
+        app_module.release_sdr_device(device_int, sdr_type_str)
+        adsb_active_device = None
+        adsb_active_sdr_type = None
         return jsonify({'status': 'error', 'message': str(e)})
 
 
 @adsb_bp.route('/stop', methods=['POST'])
 def stop_adsb():
     """Stop ADS-B tracking."""
-    global adsb_using_service, adsb_active_device
+    global adsb_using_service, adsb_active_device, adsb_active_sdr_type
     data = request.get_json(silent=True) or {}
     stop_source = data.get('source')
     stopped_by = request.remote_addr
@@ -923,10 +943,11 @@ def stop_adsb():
 
         # Release device from registry
         if adsb_active_device is not None:
-            app_module.release_sdr_device(adsb_active_device)
+            app_module.release_sdr_device(adsb_active_device, adsb_active_sdr_type or 'rtlsdr')
 
         adsb_using_service = False
         adsb_active_device = None
+        adsb_active_sdr_type = None
 
     app_module.adsb_aircraft.clear()
     _looked_up_icaos.clear()