v0.4.61: asset cache fix, PNG-enabled iPXE, composed PXE logo

Two real issues v0.4.6 left on the table:

Asset caching:
- index.html now interpolates the running OpenPXE version into every
  asset URL as `?v=<version>` (app.css, app.js, logo.svg). Combined
  with `Cache-Control: no-cache, must-revalidate` on the asset
  handlers, browsers and intermediary proxies are forced to fetch
  fresh on every upgrade. Without this, last release's bundled JS
  kept serving the old UI even after the operator pulled the new
  image — invisible to anyone who only checks the version chip in
  the footer (which is dynamic).
- The Cache-Control header is also applied to logo.svg and loader.svg
  so a logo upload reflects immediately rather than after a hard
  refresh.

Real-image PXE menu logo (matches iVentoy now):
- New Dockerfile stage `ipxe-build` clones the iPXE source and
  compiles all four binaries (undionly.kpxe, snponly.efi for
  x86_64/i386, snponly.efi for arm64 via gcc-aarch64-linux-gnu) with
  IMAGE_PNG + CONSOLE_FRAMEBUFFER + CONSOLE_VESAFB enabled. Replaces
  the boot.ipxe.org fetch — those binaries are built without PNG
  support, which is why v0.4.6's `console --picture` line silently
  no-op'd.
- `iso-store::pxe_logo::compose_pxe_logo` decodes any operator upload
  (PNG / JPEG / WebP / GIF), downscales-to-fit if larger than
  600×200, and pastes it onto a transparent 1024×768 canvas
  centered horizontally with a 64-pixel top margin. iPXE paints the
  result at 1:1 on the typical VESA framebuffer, giving the
  iVentoy-style centered-logo look regardless of the operator's
  source dimensions.
- GET /branding/pxe-logo now returns the composed PNG. wimboot still
  fetches from ipxe/wimboot's GitHub release (separately signed).
- Dropped the ASCII OpenPXE wordmark from render_menu — once the
  real image paints, the banner would duplicate it visually. iPXE
  builds without PNG (none of ours after this release, but a third-
  party undionly might) simply show the menu without a logo, which
  is the right graceful-degradation outcome.

Quality:
- 142 tests passing (was 138 in v0.4.6): +4 pxe_logo unit tests
  covering canvas dimensions, centered-top placement, oversize
  downscale, and unsupported-bytes error handling; existing
  integration tests updated to verify the 1024×768 IHDR header from
  the composed PNG instead of round-tripping the raw upload.
- cargo clippy --workspace --all-targets clean.
- Image dependency: `image = "0.25"` with only `png/jpeg/webp/gif`
  features enabled. No new transitive C deps.

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

crates/http-api/src/ipxe_script.rs

@@ -77,17 +77,15 @@ pub fn render_menu(isos: &[IsoMeta], settings: &Settings, base_url: &str) -> Str
     );
     let _ = writeln!(s, ":menu");
     let _ = writeln!(s, "menu OpenPXE - network boot menu");
-    // Centered ASCII wordmark. iPXE menus are ~76 columns wide on the
-    // default VGA text console; the lines below are padded to sit
-    // approximately centered. `item --gap -- <text>` emits text without
-    // a selectable hotkey.
-    let _ = writeln!(s, "item --gap");
-    let _ = writeln!(s, "item --gap --       ___                   ___  __  __ ___");
-    let _ = writeln!(s, "item --gap --      / _ \\ _ __  ___ _ _   | _ \\ \\/  / | __|");
-    let _ = writeln!(s, "item --gap --     | (_) | '_ \\/ -_) ' \\  |  _/  \\  /  | _|");
-    let _ = writeln!(s, "item --gap --      \\___/| .__/\\___|_||_| |_|    /_/\\_\\ |___|");
-    let _ = writeln!(s, "item --gap --           |_|");
-    let _ = writeln!(s, "item --gap");
+    // v0.4.61: we used to draw an ASCII OpenPXE wordmark here. Now
+    // that the bundled iPXE is built with `IMAGE_PNG`, the
+    // `console --picture` line at the top of this script paints the
+    // operator's actual logo (composed server-side into a 1024×768
+    // canvas with the logo centered at the top) — the ASCII banner
+    // became visual noise *on top* of the real image. Old iPXE
+    // builds without PNG fall through the `|| console` clause and
+    // simply show the menu without a logo, which is the correct
+    // graceful-degradation outcome.
     let _ = writeln!(
         s,
         "item --gap -- ------------------------- Default -------------------------"
@@ -628,10 +626,12 @@ mod password_tests {
 
     #[test]
     fn top_menu_has_polished_branding_and_arch_footer() {
-        // v0.4.6 polish: a `console --picture` line for operator
-        // logos, an ASCII OpenPXE wordmark visible across iPXE
-        // builds (graphics or not), and a single-line footer carrying
-        // the current OpenPXE version + the resolved arch label.
+        // v0.4.6 polish + v0.4.61 image upgrade: the menu emits a
+        // `console --picture` line that the bundled iPXE (built with
+        // `IMAGE_PNG`) honours, plus an arch-resolved footer carrying
+        // the current OpenPXE version. The ASCII wordmark that used
+        // to live here was dropped in v0.4.61 — it duplicated the now-
+        // working image.
         let settings = Settings::default();
         let s = render_menu(&[], &settings, "http://10.0.0.5");
         assert!(
@@ -641,11 +641,11 @@ mod password_tests {
         // Picture-or-text-console must be a single statement so older
         // iPXE parsers don't choke on the chain.
         assert!(s.contains("|| console"), "missing graceful fallback:\n{s}");
-        // ASCII wordmark — at least one of the banner lines must
-        // contain the trailing pipe segment, plus the leading "_"s.
+        // No ASCII wordmark — once the real PNG paints, the ASCII
+        // banner would duplicate the operator's logo visually.
         assert!(
-            s.contains("___                   ___  __  __ ___"),
-            "ascii banner missing first row:\n{s}"
+            !s.contains("___                   ___  __  __ ___"),
+            "ASCII banner shouldn't be emitted in v0.4.61+:\n{s}"
         );
         // Footer with version + arch interpolation. The version comes
         // from CARGO_PKG_VERSION at compile time.