feat: ✨ WebGL graphics blog post, Gerber demo on landing page, open-source license notices

- Blog: porting-kicad-graphics-to-webgl post + GAL native/WebGL comparison images and <GalCompare>
- Landing page: embed lazily-loaded Gerber demo section + footer "Live demo" link
- Licensing: /licenses page (GPLv3 + wxWindows/LGPL-v2 breakdown, ahilss credit, corresponding-source offer) and a footer build-SHA link
- Docs: CLAUDE.md + README note to bump the hardcoded footer BUILD_SHA on each release

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

site/src/components/Footer.astro

@@ -5,6 +5,13 @@ import EECredit from './EECredit.astro';
 const year = new Date().getFullYear();
 // TODO(links): add Roadmap (/roadmap) and dedicated How-it-works/Open pages when they ship.
 const GITHUB_URL = 'https://github.com/emergence-engineering';
+
+// Build provenance. Hardcoded because the site ships as static assets (R2), so
+// there's no build-time git/env to read it from. BUMP THIS to the deployed
+// main-repo (pcbjam) commit on each release — it pins the KiCad + wxWidgets
+// submodule revisions implicitly. See /licenses for the source-code offer.
+const BUILD_SHA = '695a460';
+const BUILD_COMMIT_URL = `https://github.com/emergence-engineering/pcbjam/commit/${BUILD_SHA}`;
 ---
 
 <footer class="site-footer">
@@ -28,7 +35,7 @@ const GITHUB_URL = 'https://github.com/emergence-engineering';
       <nav class="links stack" aria-label="Product">
         <a href="/#how-it-works">How it works</a>
         <a href="/#open">Open &amp; yours</a>
-        <a href="/#multiplayer">Multiplayer</a>
+        <a href="/#demo">Live demo</a>
         <a href="/#waitlist">Join the waitlist</a>
       </nav>
     </div>
@@ -44,12 +51,20 @@ const GITHUB_URL = 'https://github.com/emergence-engineering';
         <a href="/privacy">Privacy Policy</a>
         <a href="/terms">Terms of Service</a>
         <a href="/cookies">Cookie Policy</a>
+        <a href="/licenses">Open-Source Licenses</a>
       </nav>
     </div>
   </div>
 
   <div class="container bottom">
-    <span>&copy; {year} Emergence Engineering</span>
+    <span
+      >&copy; {year} Emergence Engineering &middot; <a
+        class="build"
+        href={BUILD_COMMIT_URL}
+        rel="noopener"
+        target="_blank">build {BUILD_SHA}</a
+      ></span
+    >
     <span class="attrib muted">
       Built on the open-source <a href="https://www.kicad.org" rel="noopener" target="_blank"
         >KiCad</a
@@ -124,6 +139,15 @@ const GITHUB_URL = 'https://github.com/emergence-engineering';
     font-size: 0.82rem;
     max-width: 42rem;
   }
+  .build {
+    font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
+    font-size: 0.82rem;
+    color: var(--fg-muted);
+  }
+  .build:hover {
+    color: var(--fg);
+    text-decoration: none;
+  }
 
   @media (max-width: 820px) {
     .cols {

site/src/components/GalCompare.astro

@@ -0,0 +1,128 @@
+---
+/**
+ * Native-vs-WebGL GAL comparison strips for the WebGL-port blog post.
+ *
+ * Each scenario from the GAL regression suite (tests/gal-regression) is rendered
+ * twice — once by KiCad's native OpenGL GAL, once by the new WebGL GAL — and the
+ * two are laid side by side so the reader can eyeball parity, exactly the way the
+ * suite is validated. Source PNGs are the committed baselines (1600×1200);
+ * astro:assets <Picture> emits responsive AVIF/WebP at build time.
+ */
+import { Picture } from 'astro:assets';
+import alphaNative from '../assets/gal/gal-alpha-blending-native.png';
+import alphaWebgl from '../assets/gal/gal-alpha-blending-webgl.png';
+import xfNative from '../assets/gal/gal-transform-api-native.png';
+import xfWebgl from '../assets/gal/gal-transform-api-webgl.png';
+
+const pairs = [
+  {
+    title: 'Alpha blending',
+    native: alphaNative,
+    webgl: alphaWebgl,
+    caption:
+      'Overlapping translucent fills plus a fading alpha ramp, native OpenGL and WebGL come out close.',
+  },
+  {
+    title: 'The Transform() API',
+    native: xfNative,
+    webgl: xfWebgl,
+    caption:
+      'A scenario the other way round: KiCad’s Transform() entry point is dead code on the desktop, so our "correct" implementation doesn\'t matter in the end.',
+  },
+];
+---
+
+<div class="gal-compare not-prose">
+  {pairs.map((p) => (
+    <figure class="gal-pair">
+      <div class="gal-pair__grid">
+        <div class="gal-shot">
+          <span class="gal-shot__tag">Native OpenGL</span>
+          <Picture
+            src={p.native}
+            formats={['avif', 'webp']}
+            widths={[320, 640, 800]}
+            sizes="(max-width: 700px) 90vw, 340px"
+            alt={`${p.title} rendered by KiCad's native OpenGL GAL`}
+            loading="lazy"
+            decoding="async"
+          />
+        </div>
+        <div class="gal-shot">
+          <span class="gal-shot__tag gal-shot__tag--webgl">WebGL</span>
+          <Picture
+            src={p.webgl}
+            formats={['avif', 'webp']}
+            widths={[320, 640, 800]}
+            sizes="(max-width: 700px) 90vw, 340px"
+            alt={`${p.title} rendered by the new WebGL GAL`}
+            loading="lazy"
+            decoding="async"
+          />
+        </div>
+      </div>
+      <figcaption><strong>{p.title}.</strong> {p.caption}</figcaption>
+    </figure>
+  ))}
+</div>
+
+<style>
+  .gal-compare {
+    display: grid;
+    gap: 1.75rem;
+    margin: 2rem 0;
+  }
+  .gal-pair {
+    margin: 0;
+  }
+  .gal-pair__grid {
+    display: grid;
+    grid-template-columns: 1fr 1fr;
+    gap: 0.6rem;
+  }
+  .gal-shot {
+    position: relative;
+    border: 1px solid var(--border);
+    border-radius: var(--radius);
+    overflow: hidden;
+    background: var(--bg-soft);
+  }
+  /* astro:assets <Picture> emits the <img>; style it globally within the shot. */
+  .gal-shot :global(img) {
+    display: block;
+    width: 100%;
+    height: auto;
+    aspect-ratio: 4 / 3;
+    object-fit: contain;
+  }
+  .gal-shot__tag {
+    position: absolute;
+    top: 0.4rem;
+    left: 0.4rem;
+    z-index: 1;
+    font-family: var(--font-mono);
+    font-size: 0.66rem;
+    letter-spacing: 0.02em;
+    color: var(--fg);
+    background: rgba(11, 16, 32, 0.82);
+    border: 1px solid var(--border);
+    border-radius: var(--radius-sm);
+    padding: 0.12rem 0.4rem;
+  }
+  .gal-shot__tag--webgl {
+    color: #fff;
+    background: var(--brand-600);
+    border-color: transparent;
+  }
+  .gal-pair figcaption {
+    margin-top: 0.6rem;
+    font-size: 0.85rem;
+    line-height: 1.5;
+    color: var(--fg-muted);
+  }
+  @media (max-width: 460px) {
+    .gal-pair__grid {
+      grid-template-columns: 1fr;
+    }
+  }
+</style>

site/src/components/GerberDemo.astro

@@ -16,7 +16,7 @@
  */
 const poster = "/gerber-demo/poster.png"; // captured screenshot; optional fallback art
 const caption =
-  "KiCad's Gerber viewer (gerbview), compiled to WebAssembly, running the tiny_tapeout demo board entirely in your browser.";
+  "KiCad's Gerber viewer compiled to WebAssembly, running the tiny_tapeout demo board ";
 ---
 
 <figure class="gerber-demo not-prose" data-state="idle">