Implement M1.5 visual design foundation: tokens, IBM Plex, theme toggle, chart themes

vite.config.ts

@@ -41,9 +41,16 @@ export default defineConfig({
         theme_color: '#1a1a2e',
         background_color: '#ffffff',
         display: 'standalone',
+        // TODO: theme_color/background_color are stale placeholders — '#1a1a2e' was
+        // the old --color-text hex, retired by the M1.5 token rename. Re-pick from
+        // the settled palette (and reconcile with light/dark) when icons land.
         icons: [],
       },
       workbox: {
+        // Workbox's default globPatterns omit woff2; add it so the self-hosted
+        // Plex fonts are precached too (offline is a core requirement — without
+        // this the first offline load silently falls back to system fonts).
+        globPatterns: ['**/*.{js,css,html,ico,png,svg,woff2}'],
         // Monaco and Vega vendor chunks exceed Workbox's 2 MiB default; raise the
         // ceiling so the whole app (offline is a core requirement) is precached.
         maximumFileSizeToCacheInBytes: 6 * 1024 * 1024,