feat(mobile): add the mobile app shell, capture and the /mobile/ build page

Five tabs (Now, Globe, Capture, Threads, You) over one persistent globe:
a live situation feed whose cards open into the world with a detented
brief, the lens dock and time ribbon, AR Look and signed Witness
capture (ECDSA P-256 in IndexedDB, SHA-256 hash chain, IMU and GPS
trace, eight-check verify), the Bhote Koshi reconstruction thread with
a live ledger, and hinge-aware two-pane layouts for foldables.

The production build now emits mobile/index.html beside the app; the
panel build keeps the app alone.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01VVYRAqiQj9Y1V9ZfG1RcDH

mobile/ui/feed.js

@@ -136,7 +136,11 @@ export function createFeed(
     }
     return all
       .filter((s) => !isReconstruction(s) && !isAlwaysOn(s))
-      .sort((a, b) => new Date(b.updatedAt) - new Date(a.updatedAt));
+      .sort(
+        (a, b) =>
+          (b.severity ?? 0) - (a.severity ?? 0) ||
+          new Date(b.updatedAt) - new Date(a.updatedAt),
+      );
   }
 
   function render() {