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/components/Stats.tsx

@@ -1,3 +1,4 @@
+import { Icon } from "./Icon";
 import { useMemo, useState } from "react";
 import { useFetch } from "../hooks";
 import { fmtCompact, fmtCost, fmtDate, fmtNumber, fmtPercent, getLang, useT, weekdayNames, type Key } from "../i18n";
@@ -163,7 +164,7 @@ export function Stats({ onMenu }: { onMenu: () => void }) {
     <>
       <div className="topbar">
         <button className="ghost menu-btn" onClick={onMenu} aria-label={t("nav.menu")}>
-          ☰
+          <Icon name="menu" />
         </button>
         <div className="grow">
           <h1>{t("nav.stats")}</h1>