Add Web Push, guided start screen, SVG icons, chunked uploads, rename

- Web Push (VAPID + RFC 8291, pure Rust): permission/question/finished
  notifications while no app window is visible; settings with test button
- Guided new-session flow: task, craft target (website/app/game/old
  software/fresh), clean room or deep, description, model, folder
  (new, existing or cloned git repository); originals upload to original/
- Craft phase bar (craft_phase tool) for study/specify/build/check/ready
- Chunked uploads (8 MB) up to server.max_upload_mb (default 500 MB)
- All UI glyphs and emojis replaced by themeable SVG icons
- Rename dialog with manual name or model-generated suggestion

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/store.ts

@@ -197,6 +197,8 @@ export function applyEvent(ev: ServerEvent) {
 /** Notify when the app is in the background and an agent needs input. */
 function notify(body: string) {
   if (document.visibilityState === "visible" || !("Notification" in window)) return;
+  // With Web Push on this device the server notifies (avoid duplicates).
+  if (localStorage.getItem("codecraft.push") === "1") return;
   if (Notification.permission === "granted") {
     new Notification("CodeCraft", { body, icon: "/icon-192.png" });
   }