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/dialogs.tsx

@@ -1,3 +1,4 @@
+import { Icon } from "./components/Icon";
 // In-app dialogs and toasts instead of the browser's alert/confirm/prompt.
 import { useEffect, useRef, useState, useSyncExternalStore } from "react";
 import { t } from "./i18n";
@@ -132,7 +133,7 @@ export function DialogHost() {
       <div className="toasts" role="status" aria-live="polite">
         {ts.map((x) => (
           <div key={x.id} className={`toast ${x.kind}`} onClick={() => ((toasts = toasts.filter((y) => y.id !== x.id)), emit())}>
-            {x.kind === "error" ? "⚠ " : x.kind === "success" ? "✓ " : ""}
+            {x.kind === "error" ? <Icon name="warning" /> : x.kind === "success" ? <Icon name="check" /> : null}
             {x.message}
           </div>
         ))}