Add rtlamr utility meter monitoring support

- Added rtlamr mode for decoding utility meters (water, gas, electric)
- Starts rtl_tcp server first, then connects rtlamr to it
- Supports multiple message types: SCM, SCM+, IDM, NetIDM, R900, R900 BCD
- Added frequency presets for 912 MHz (NA) and 868 MHz (EU)
- Includes meter ID filtering and unique message options
- Updated setup.sh to check and install rtlamr and rtl_tcp
- Added UI components: navigation button, mode template, JavaScript functions
- Integrated into SDR/RF dropdown menu with lightning bolt icon
- Updates mode indicator with frequency when listening
- Added help documentation and requirements section

app.py

@@ -134,6 +134,11 @@ aprs_rtl_process = None
 aprs_queue = queue.Queue(maxsize=QUEUE_MAX_SIZE)
 aprs_lock = threading.Lock()
 
+# RTLAMR utility meter reading
+rtlamr_process = None
+rtlamr_queue = queue.Queue(maxsize=QUEUE_MAX_SIZE)
+rtlamr_lock = threading.Lock()
+
 # TSCM (Technical Surveillance Countermeasures)
 tscm_queue = queue.Queue(maxsize=QUEUE_MAX_SIZE)
 tscm_lock = threading.Lock()
@@ -225,7 +230,8 @@ def index() -> str:
     tools = {
         'rtl_fm': check_tool('rtl_fm'),
         'multimon': check_tool('multimon-ng'),
-        'rtl_433': check_tool('rtl_433')
+        'rtl_433': check_tool('rtl_433'),
+        'rtlamr': check_tool('rtlamr')
     }
     devices = [d.to_dict() for d in SDRFactory.detect_devices()]
     return render_template('index.html', tools=tools, devices=devices, version=VERSION, changelog=CHANGELOG)