Fix floor persistence and improve movement detection

- Store floor assignments in SQLite database for persistence
- Floor now saves correctly for live-tracked BT devices
- Add statistical movement detection (5-sample average + stddev)
- Require 1.5m + 2σ deviation to mark device as moving
- Reduces false positives from RSSI noise/fluctuations
- Add /api/device/floors endpoint for bulk floor retrieval

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

src/rf_mapper/web/static/js/app.js

@@ -21,9 +21,72 @@ let liveTrackingEnabled = false;
 let liveTrackingInterval = null;
 const LIVE_TRACKING_INTERVAL_MS = 4000; // 4 seconds
 
-// Track previous distances for movement detection
-let previousDistances = {};
-const MOVEMENT_THRESHOLD = 0.5; // meters - consider moving if distance changed by this much
+// Statistical movement detection
+const SAMPLE_HISTORY_SIZE = 5;  // Number of samples to keep for averaging
+const MOVEMENT_THRESHOLD = 1.5; // meters - movement must exceed this + stddev margin
+const MIN_SAMPLES_FOR_MOVEMENT = 3; // Need at least this many samples before detecting movement
+
+// Store distance history per device: { address: { samples: [], timestamps: [] } }
+let deviceDistanceHistory = {};
+
+// Calculate mean of array
+function mean(arr) {
+    if (arr.length === 0) return 0;
+    return arr.reduce((a, b) => a + b, 0) / arr.length;
+}
+
+// Calculate standard deviation
+function stddev(arr) {
+    if (arr.length < 2) return 0;
+    const avg = mean(arr);
+    const squareDiffs = arr.map(x => Math.pow(x - avg, 2));
+    return Math.sqrt(mean(squareDiffs));
+}
+
+// Check if device is moving based on statistical analysis
+function isDeviceMoving(address, newDistance) {
+    // Initialize history if needed
+    if (!deviceDistanceHistory[address]) {
+        deviceDistanceHistory[address] = { samples: [], timestamps: [] };
+    }
+
+    const history = deviceDistanceHistory[address];
+    const now = Date.now();
+
+    // Add new sample
+    history.samples.push(newDistance);
+    history.timestamps.push(now);
+
+    // Remove old samples (keep last SAMPLE_HISTORY_SIZE)
+    while (history.samples.length > SAMPLE_HISTORY_SIZE) {
+        history.samples.shift();
+        history.timestamps.shift();
+    }
+
+    // Need minimum samples to determine movement
+    if (history.samples.length < MIN_SAMPLES_FOR_MOVEMENT) {
+        return false;
+    }
+
+    // Calculate statistics from older samples (exclude the newest one)
+    const olderSamples = history.samples.slice(0, -1);
+    const avg = mean(olderSamples);
+    const sd = stddev(olderSamples);
+
+    // Movement threshold = base threshold + 2 standard deviations (95% confidence)
+    const dynamicThreshold = MOVEMENT_THRESHOLD + (2 * sd);
+
+    // Check if current reading deviates significantly from the average
+    const deviation = Math.abs(newDistance - avg);
+    const isMoving = deviation > dynamicThreshold;
+
+    // Debug log for significant movements
+    if (isMoving) {
+        console.log(`[Movement] ${address}: dist=${newDistance.toFixed(2)}m, avg=${avg.toFixed(2)}m, sd=${sd.toFixed(2)}, threshold=${dynamicThreshold.toFixed(2)}m`);
+    }
+
+    return isMoving;
+}
 
 // Device positions for hit detection (radar view)
 let devicePositions = [];
@@ -1485,23 +1548,19 @@ async function performLiveBTScan() {
                     const existing = existingBt.find(d => d.address === newDev.address);
                     const newDist = newDev.estimated_distance_m;
 
-                    // Check for movement
-                    const prevDist = previousDistances[newDev.address];
-                    const isMoving = prevDist !== undefined && Math.abs(newDist - prevDist) > MOVEMENT_THRESHOLD;
-
-                    // Store current distance for next comparison
-                    previousDistances[newDev.address] = newDist;
+                    // Check for movement using statistical analysis
+                    const moving = isDeviceMoving(newDev.address, newDist);
 
                     if (existing) {
                         // Update RSSI and estimated distance, preserve custom values
                         existing.rssi = newDev.rssi;
                         existing.estimated_distance_m = newDev.estimated_distance_m;
                         existing.signal_quality = newDev.signal_quality;
-                        existing.is_moving = isMoving;
+                        existing.is_moving = moving;
                         // Preserve floor and custom_distance_m if set
                     } else {
                         // New device, add it
-                        newDev.is_moving = isMoving;
+                        newDev.is_moving = moving;
                         existingBt.push(newDev);
                     }
                 });
@@ -1510,7 +1569,8 @@ async function performLiveBTScan() {
             } else {
                 // No existing scan data, use BT-only data
                 data.bluetooth_devices.forEach(dev => {
-                    previousDistances[dev.address] = dev.estimated_distance_m;
+                    // Initialize history with first sample, not moving yet
+                    isDeviceMoving(dev.address, dev.estimated_distance_m);
                     dev.is_moving = false;
                 });
                 scanData = {