fix: video fills available space + correct WASM path resolution

- Remove fixed aspect-ratio and max-height from video panel so it
  fills the available viewport space without scrolling
- Grid uses 1fr row for content area, overflow:hidden on main grid
- Fix WASM path: resolve relative to JS module file using import.meta.url
  instead of hardcoded ./pkg/ which resolved incorrectly on gh-pages
- Responsive: mobile still gets aspect-ratio constraint

Co-Authored-By: claude-flow <ruv@ruv.net>

ui/pose-fusion/js/main.js

@@ -111,8 +111,10 @@ function init() {
   });
 
   // Try to load WASM embedders (non-blocking)
-  visualCnn.tryLoadWasm('./pkg/ruvector_cnn_wasm');
-  csiCnn.tryLoadWasm('./pkg/ruvector_cnn_wasm');
+  // Resolve relative to this JS module file (in pose-fusion/js/) → ../pkg/
+  const wasmBase = new URL('../pkg/ruvector_cnn_wasm', import.meta.url).href;
+  visualCnn.tryLoadWasm(wasmBase);
+  csiCnn.tryLoadWasm(wasmBase);
 
   // Auto-start camera for video/dual modes
   updateModeUI();