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/types.ts

@@ -58,6 +58,8 @@ export interface Session {
   owner_id?: string | null;
   /** Craft: clean room (true) or deep (false); undefined = server default. */
   clean_room?: boolean | null;
+  /** Craft workflow phase reported by the agent. */
+  phase?: string;
   /** Listed because it was shared with the current user. */
   shared?: boolean;
 }