feat: add peer sync for multi-scanner deployments

Enable scanner instances to discover each other and synchronize
device metadata (floors, positions, labels, favorites) automatically.

New features:
- Peer registration API with mutual auto-registration
- Background sync thread with configurable interval
- Timestamp-based conflict resolution (newest wins)
- Config options: peers, sync_interval_seconds, accept_registrations

API endpoints:
- GET/POST /api/peers - list peers, register new peer
- DELETE /api/peers/<id> - remove peer
- GET/POST /api/sync/devices - device sync for peers
- POST /api/sync/trigger - manual sync trigger

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

config.yaml

@@ -1,70 +1,55 @@
-# RF Mapper Configuration
-# ========================
-
-# GPS Reference Position
-# Set this to your Home Assistant or scanner location
 gps:
-  # Belgium (Brussels area) - Update with your actual coordinates
-  latitude: 50.8585853
-  longitude: 4.3978724
-  # You can get precise coordinates from Home Assistant at:
-  # http://192.168.129.10:8123/config/zone
-
-# Web Server Settings
+  latitude: 50.85852913116932
+  longitude: 4.3976058563598315
 web:
-  host: "0.0.0.0"
+  host: 0.0.0.0
   port: 5000
   debug: false
-
-# Scanner Settings
 scanner:
-  # WiFi interface name
-  wifi_interface: "wlan0"
-  # Bluetooth scan timeout in seconds
+  id: ''
+  name: ''
+  latitude: null
+  longitude: null
+  floor: null
+  wifi_interface: wlan0
   bt_scan_timeout: 10
-  # Path loss exponent for distance estimation
-  # 2.0 = free space, 2.5 = light indoor, 3.0-4.0 = walls
   path_loss_exponent: 2.5
-  # Automatically identify Bluetooth devices (queries device services)
-  auto_identify_bluetooth: true
-
-# Data Storage
+  wifi_tx_power: -59
+  bt_tx_power: -72
+  # Peer sync settings
+  peers: []                     # List of peer scanner URLs (auto-populated via registration)
+  sync_interval_seconds: 30     # How often to sync with peers (0 = disabled)
+  accept_registrations: true    # Allow other scanners to register with this one
 data:
-  # Directory for scan data (relative to project root or absolute path)
-  directory: "data"
-  # Maximum number of scans to keep (0 = unlimited)
+  directory: data
   max_scans: 100
-
-# SQLite Database for Device History
 database:
-  # Enable historical tracking
   enabled: true
-  # Database filename (stored in data directory)
-  filename: "devices.db"
-  # Data retention period in days (auto-cleanup older data)
+  filename: devices.db
   retention_days: 30
-  # Enable automatic daily cleanup
   auto_cleanup: true
-
-# Home Assistant Integration (optional)
 home_assistant:
-  enabled: false
-  url: "http://192.168.129.10:8123"
-  # Token can be set here or via HA_TOKEN environment variable
-  # Generate at: http://192.168.129.10:8123/profile -> Long-Lived Access Tokens
-  token: ""
-
-# Building Configuration (for 3D map view)
-building:
-  # Enable 3D building visualization
   enabled: true
-  # Building name (displayed in UI)
-  name: "Home"
-  # Number of floors in the building
+  url: http://192.168.129.10:8123
+  token: ''
+  webhook_scan: rf_mapper_scan
+  webhook_new_device: rf_mapper_new_device
+  webhook_device_gone: rf_mapper_device_gone
+  device_timeout_minutes: 5
+profiling:
+  enabled: false
+  cpu: true
+  memory: false
+  output_dir: data/profiles
+  sort_by: cumtime
+auto_scan:
+  enabled: false
+  interval_minutes: 5
+  location_label: auto_scan
+building:
+  enabled: true
+  name: Home
   floors: 12
-  # Height of each floor in meters
   floor_height_m: 3.0
-  # Ground floor number (0 in most countries, 1 in US)
   ground_floor_number: 0
-  # Scanner's current floor (devices scanned will be assigned to this floor)
   current_floor: 11