Switch to bleak for reliable BLE scanning with RSSI

- Replace hcitool-based BT scanning with bleak Python library
- Bleak provides reliable RSSI values via D-Bus/BlueZ
- BLE scan now finds devices that hcitool missed
- Update project docs to reflect resolved BT RSSI blocker
- Add bleak>=0.21.0 to dependencies

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/rf_mapper/web/app.py

@@ -814,61 +814,32 @@ def create_app(config: Config | None = None) -> Flask:
 
     @app.route("/api/scan/bt", methods=["POST"])
     def api_scan_bt():
-        """Quick Bluetooth-only scan for real-time tracking using hcitool"""
-        import subprocess
-        import re
+        """Quick Bluetooth-only scan for real-time tracking using bleak (BLE)"""
+        import asyncio
+        from bleak import BleakScanner
 
         bt = []
         try:
-            # Use hcitool inq for classic BT (more reliable)
-            result = subprocess.run(
-                ['sudo', 'hcitool', 'inq', '--flush'],
-                capture_output=True,
-                text=True,
-                timeout=12
-            )
-
-            for line in result.stdout.split('\n'):
-                # Parse: "	E0:03:6B:FE:24:A1	clock offset: 0x15c7	class: 0x08043c"
-                m = re.match(r'\s*([0-9A-Fa-f:]+)\s+clock offset.*class:\s*0x([0-9A-Fa-f]+)', line)
-                if m:
-                    addr = m.group(1)
-                    device_class = m.group(2)
-
-                    # Get device name
-                    name = '<unknown>'
-                    try:
-                        name_result = subprocess.run(
-                            ['sudo', 'hcitool', 'name', addr],
-                            capture_output=True, text=True, timeout=5
-                        )
-                        if name_result.stdout.strip():
-                            name = name_result.stdout.strip()
-                    except:
-                        pass
-
-                    # Get RSSI (only works if device is connectable)
-                    rssi = -70  # Default
-                    try:
-                        rssi_result = subprocess.run(
-                            ['sudo', 'hcitool', 'rssi', addr],
-                            capture_output=True, text=True, timeout=3
-                        )
-                        rssi_match = re.search(r'RSSI return value:\s*(-?\d+)', rssi_result.stdout)
-                        if rssi_match:
-                            rssi = int(rssi_match.group(1))
-                    except:
-                        pass
-
-                    bt.append({
+            async def do_scan():
+                devices = await BleakScanner.discover(timeout=3.0, return_adv=True)
+                results = []
+                for addr, (device, adv) in devices.items():
+                    rssi = adv.rssi if adv else -70
+                    name = device.name or '<unknown>'
+                    results.append({
                         'address': addr,
                         'name': name,
                         'rssi': rssi,
-                        'device_class': device_class
+                        'device_class': 'BLE'
                     })
+                return results
+
+            # Run async scan in sync context
+            bt = asyncio.run(do_scan())
+            print(f"[BT] Bleak scan found {len(bt)} devices")
 
         except Exception as e:
-            print(f"[BT] hcitool scan error: {e}")
+            print(f"[BT] Bleak scan error: {e}")
             bt = []
 
         # The scanner already does auto-identification if enabled