Add syntax highlighting, OSD, search, perf optimizations, and UX improvements

- troika-three-text MSDF rendering for resolution-independent code text
- highlight.js syntax highlighting with Catppuccin Mocha colors
- Lazy text pool: max 25 concurrent code meshes, created on demand
- LOD throttled to every 3 frames, OSD every 10
- 45° tiled watermark (repo/path/filename) behind code
- OSD: breadcrumb, file stats, zoom level
- Search: / or Ctrl+F to find and fly to files
- Keybindings: WASD pan, Q/E rotate, Z/C zoom, Space overview, ? help modal
- Mouse wheel zoom vs trackpad pan detection via event frequency
- Zip GBK filename encoding fallback for Chinese filenames
- Docker volume persistence for SQLite cache

web/package.json

@@ -9,7 +9,9 @@
   },
   "dependencies": {
     "d3-hierarchy": "^3.1.2",
-    "three": "^0.170.0"
+    "highlight.js": "^11.11.1",
+    "three": "^0.170.0",
+    "troika-three-text": "^0.52.4"
   },
   "devDependencies": {
     "vite": "^6.0.0"