refactor: streamline RSVP reader for The Well of Ascension single-book focus

- Clean up legacy multi-format/CJK modules (orp, epub, samples, modals)
- Replace with lightweight pure English tokenizer and chunking engine
- Add SettingsDrawer, auto-hiding HUD, and PWA icons
- Update manifest and touch icons

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

public/manifest.json

@@ -0,0 +1,23 @@
+{
+  "name": "Focus",
+  "short_name": "Focus",
+  "start_url": "/",
+  "display": "standalone",
+  "background_color": "#09090b",
+  "theme_color": "#09090b",
+  "description": "极速词流专注器",
+  "icons": [
+    {
+      "src": "/pwa-192.png",
+      "sizes": "192x192",
+      "type": "image/png",
+      "purpose": "any maskable"
+    },
+    {
+      "src": "/pwa-512.png",
+      "sizes": "512x512",
+      "type": "image/png",
+      "purpose": "any maskable"
+    }
+  ]
+}