v0.4.6: iVentoy-style PXE menu, top-right user menu, Settings touchups

PXE boot menu polish (iVentoy-inspired):
- render_menu now opens with a best-effort `console --picture
  <base>/branding/pxe-logo || console` line so iPXE builds with PNG
  support paint the operator's uploaded raster logo as the background.
- ASCII OpenPXE wordmark banner sits at the top of the menu in
  `item --gap` lines — always visible on every iPXE build, including
  the snponly/undionly variants without graphics console.
- New footer line above `choose`: "OpenPXE v0.4.6 - <arch label>",
  where <arch label> is mapped from iPXE's ${buildarch}/${platform}
  to "x86 BIOS", "x86_64 UEFI", or "arm64 UEFI". No URL, per brief.
- New GET /branding/pxe-logo route serves the operator's PNG / JPEG /
  WebP / GIF as-is for iPXE to consume. SVG uploads 404 here (iPXE
  can't rasterize SVG) — the always-visible ASCII wordmark stands in.
  Route stays public after admin setup so iPXE clients (no cookies)
  can fetch it.

UI:
- Removed the bottom-left "signed in as / Sign out" row.
- Added a person-icon button next to the theme toggle in the topbar.
  Click opens a small popover with: Name (display only), Edit account
  (jumps to Settings), Sign out. Esc + click-outside close it.
- Settings → Account card form chrome made consistent. The previous
  `label.field` selector only styled type=text/number, leaving
  password inputs with default browser chrome. Switched to a
  negation-list selector that covers every typed input we use, plus
  -webkit-appearance:none + a 1px focus ring. Light + dark mode both
  show the same border/padding/focus state across all four account
  fields.
- Settings → SSO card now renders display name, IdP logo URL (new),
  and metadata source on one 3-column row. The metadata <select>
  inherits the same chrome as the text inputs so it baseline-aligns
  with them. SsoConfig grew an idp_logo_url field, persisted to
  sso.json, length-capped and validated to http(s) only.

Quality:
- 138 tests passing (was 132 in v0.4.5). +1 IdP-logo-URL validation,
  +1 PXE menu polish regression guard, +4 /branding/pxe-logo
  integration tests covering missing-config / SVG-fallback / raster-
  serve / post-auth public-allowlist cases.
- cargo clippy --workspace --all-targets clean.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

crates/webui/src/index.html

@@ -59,15 +59,7 @@
       <!-- The brand badge at the top can be overridden by operator-uploaded
            logos; keep "OpenPXE v…" pinned in the footer so the backend
            identity is always visible regardless of branding. -->
-      <div class="footer-version">OpenPXE&nbsp;v<span data-bind="version">0.4.5</span></div>
-      <!-- v0.4.5: signed-in identity + one-click sign-out. The button
-           is populated by app.js after /api/me reports an authenticated
-           session — pre-auth states swap the whole shell for the
-           login/setup card so this row never gets shown there. -->
-      <div class="logout-row" data-bind="logout_row" style="display:none">
-        <span class="who" data-bind="signed_in_as" title=""></span>
-        <button type="button" class="logout-btn" data-bind="logout_btn">Sign out</button>
-      </div>
+      <div class="footer-version">OpenPXE&nbsp;v<span data-bind="version">0.4.6</span></div>
     </div>
   </aside>
 
@@ -97,6 +89,27 @@
         <path d="M20.5 14A8 8 0 0 1 10 3.5 a8 8 0 1 0 10.5 10.5z"/>
       </svg>
     </button>
+
+    <!-- v0.4.6: signed-in operator menu. Sits next to the theme toggle
+         in the top-right corner so the sidebar footer stays clean for
+         the "Service status / Advertised URL / Backend version" trio.
+         The whole block is hidden until /api/me confirms a session. -->
+    <div class="user-menu" data-bind="user_menu_wrap" style="display:none">
+      <button id="user-menu-btn" class="user-btn" type="button"
+              aria-label="Account menu" aria-haspopup="true" aria-expanded="false"
+              title="Account">
+        <svg viewBox="0 0 24 24" width="18" height="18" fill="none"
+             stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+          <circle cx="12" cy="8" r="3.6"/>
+          <path d="M4.5 20a7.5 7.5 0 0 1 15 0"/>
+        </svg>
+      </button>
+      <div id="user-menu-pop" class="user-pop" data-bind="user_menu_pop" hidden>
+        <div class="user-pop-name" data-bind="user_pop_name">—</div>
+        <button type="button" class="user-pop-item" data-bind="user_pop_edit">Edit account</button>
+        <button type="button" class="user-pop-item user-pop-danger" data-bind="user_pop_logout">Sign out</button>
+      </div>
+    </div>
   </header>
 
   <main class="main" id="view-root"></main>