Add AMS humidity/temperature history tracking with charts

- Add database model for storing AMS sensor history (humidity, temperature)
  - Record sensor data every 5 minutes via background task
  - Add API endpoint to retrieve history with min/max/avg statistics
  - Create AMSHistoryModal component with Recharts line charts
  - Make humidity/temperature indicators clickable to open history
  - Support time range selection (6h, 24h, 48h, 7d)
  - Show threshold reference lines on charts (Good/Fair levels)
  - Add configurable data retention (default 30 days) in Settings
  - Auto-cleanup old data daily
  - Fix dark theme styling in modal using inline styles
  - Add Escape key to close modal

static/index.html

@@ -23,8 +23,8 @@
 
     <!-- Splash screens for iOS -->
     <link rel="apple-touch-startup-image" href="/img/android-chrome-512x512.png" />
-    <script type="module" crossorigin src="/assets/index-C2iKZTlc.js"></script>
-    <link rel="stylesheet" crossorigin href="/assets/index-Bwdh7UG9.css">
+    <script type="module" crossorigin src="/assets/index-CRQNt4-E.js"></script>
+    <link rel="stylesheet" crossorigin href="/assets/index-Bz7SiJBw.css">
   </head>
   <body>
     <div id="root"></div>