Show current weather on the Overview

Add a weather card to the Web App Overview, wired like the OpenSky live-map
overlay and backed by the OpenWeather plugin.

- API Server: GET /api/integrations/openweather/current resolves the
  caller's cascade, gates it (master/org/personal opt-in/key), and returns
  trimmed current conditions for the configured or a supplied ?lat=&lon=
  point; off/keyless returns {unavailable, detail} so the card degrades.
- BFF relay (forwards the location override) + route; api.js client.
- Dashboard: a Weather card stacked above Schedule showing an emoji
  condition, temperature in the resolved unit, description, location, and a
  feels-like/wind/humidity/cloud grid. Location follows the same cascade as
  the map (drone -> phone -> browser -> default) without prompting for geo;
  refreshes every 10 min while on Overview.
- validLatLon test; rebuilt embedded frontend.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Web App/server/dist/index.html

@@ -35,8 +35,8 @@
       })()
     </script>
     <title>PilotVault — Control Panel</title>
-    <script type="module" crossorigin src="./assets/index-B-DwId4e.js"></script>
-    <link rel="stylesheet" crossorigin href="./assets/index-Dr5W1RO_.css">
+    <script type="module" crossorigin src="./assets/index-DWe3LEIB.js"></script>
+    <link rel="stylesheet" crossorigin href="./assets/index-buxVzOVb.css">
   </head>
   <body>
     <div id="app"></div>