feat(site): link the live demo + serve the gerber demo from the versioned CDN

Refer to demo.pcbjam.com from the landing: an accent "Live demo" link in the
header nav, an "Open the live editor" hero link, a note in the gerber section,
and a "Try the live demo now" line in the final CTA.

Rework the embedded gerber viewer (public/gerber-demo/boot.js) to source the
WASM from the deploy pipeline's versioned CDN instead of the hand-synced
assets.pcbjam.com bucket: resolve gerbview's content-addressed folder at runtime
from the release manifest (manifest-latest -> tag -> manifest-<tag> -> gerbview),
load all assets (glue + wasm + images.tar.gz) from cdn.pcbjam.com, and load the
cross-origin pthread worker via a same-origin blob importScripts shim (mirrors
web/standalone/src/wasm/boot.ts). Bump the config-seed KICAD_VERSION_DIR
9.99 -> 10.0 to match the deployed build. Drop the now-obsolete committed glue
mirror and the old assets.pcbjam.com sync/r2-deploy scripts.

Collapse the header nav to the hamburger below 1025px — the added demo link no
longer fits the 1024px-capped bar on a single row.

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

site/src/components/Header.astro

@@ -11,6 +11,9 @@ const links = [
     label: 'Built by Emergence Engineering',
     external: true,
   },
+  // Highlighted (accent) link to the public editor demo. A compact text link, not
+  // a button — the header container caps at 1024px and a second button overflows it.
+  { href: 'https://demo.pcbjam.com', label: 'Live demo', external: true, highlight: true },
 ];
 
 const path = Astro.url.pathname;
@@ -36,6 +39,7 @@ const isActive = (href: string, external?: boolean) =>
         links.map((l) => (
           <a
             href={l.href}
+            class:list={[{ 'nav-cta': l.highlight }]}
             aria-current={isActive(l.href, l.external) ? 'page' : undefined}
             rel={l.external ? 'noopener' : undefined}
             target={l.external ? '_blank' : undefined}
@@ -87,11 +91,12 @@ const isActive = (href: string, external?: boolean) =>
   .nav {
     display: flex;
     align-items: center;
-    gap: 1.1rem;
+    gap: 1rem;
   }
   .nav > a {
     color: var(--fg-muted);
     font-size: 0.95rem;
+    white-space: nowrap;
   }
   .nav > a:hover {
     color: var(--fg);
@@ -100,6 +105,15 @@ const isActive = (href: string, external?: boolean) =>
   .nav > a[aria-current='page'] {
     color: var(--fg);
   }
+  /* Highlighted demo link — accent-colored so it stands out among the neutral
+     nav links without needing a second button (which would overflow the bar). */
+  .nav > a.nav-cta {
+    color: var(--accent);
+    font-weight: 600;
+  }
+  .nav > a.nav-cta:hover {
+    filter: brightness(1.1);
+  }
   .cta-join {
     padding-block: 0.5rem;
     font-size: 0.95rem;
@@ -120,7 +134,10 @@ const isActive = (href: string, external?: boolean) =>
     border-radius: 2px;
   }
 
-  @media (max-width: 820px) {
+  /* Collapse to the hamburger menu once the full one-line nav no longer fits the
+     1024px-capped bar (adding the demo link pushed the crowded desktop nav past
+     the point where it stays on a single row). */
+  @media (max-width: 1024px) {
     .brand-chip {
       display: none;
     }

site/src/sections/FinalCta.astro

@@ -16,6 +16,13 @@ import WaitlistForm from '../components/WaitlistForm.astro';
       microcopy="Get early-access invites and product updates. No spam, unsubscribe anytime."
     />
 
+    <p class="final-demo">
+      Don’t want to wait? <a
+        href="https://demo.pcbjam.com"
+        target="_blank"
+        rel="noopener">Try the live demo now →</a>
+    </p>
+
     <ul class="final-trust">
       <li>Open source</li>
       <li>Built on KiCad</li>
@@ -37,6 +44,15 @@ import WaitlistForm from '../components/WaitlistForm.astro';
     margin-top: 1.5rem;
     text-align: left;
   }
+  .final-demo {
+    margin: 1rem 0 0;
+    font-size: 0.95rem;
+    color: var(--fg-muted);
+  }
+  .final-demo a {
+    color: var(--accent);
+    font-weight: 600;
+  }
   .final-trust {
     list-style: none;
     display: flex;

site/src/sections/GerberDemoSection.astro

@@ -15,6 +15,8 @@ import SectionBand from '../components/SectionBand.astro';
 // in a new tab so the landing page itself never needs isolation.
 const DEMO_HREF = '/gerber-demo/index.html';
 const poster = '/gerber-demo/poster.png';
+// The full in-browser editor (not just the viewer) — the public demo.
+const EDITOR_URL = 'https://demo.pcbjam.com';
 ---
 
 <SectionBand id="demo" labelledby="gerber-demo-h2">
@@ -40,6 +42,12 @@ const poster = '/gerber-demo/poster.png';
     <span class="gerber-launch__cta">Launch the live Gerber viewer</span>
     <span class="gerber-launch__sub">Opens in a new tab · streams ~22&nbsp;MB on demand</span>
   </a>
+
+  <p class="demo-note">
+    Want to do more than look? Open a board in the full editor at
+    <a href={EDITOR_URL} target="_blank" rel="noopener">demo.pcbjam.com</a> — edit
+    the PCB or schematic in your browser, no install, no account.
+  </p>
 </SectionBand>
 
 <style>
@@ -99,6 +107,16 @@ const poster = '/gerber-demo/poster.png';
     text-align: center;
     padding: 0 1rem;
   }
+  .demo-note {
+    margin: 1rem 0 0;
+    text-align: center;
+    color: var(--fg-muted);
+    font-size: 0.95rem;
+  }
+  .demo-note a {
+    color: var(--accent);
+    font-weight: 600;
+  }
   @media (prefers-reduced-motion: reduce) {
     .gerber-launch {
       transition: none;

site/src/sections/Hero.astro

@@ -18,6 +18,15 @@ import Icon from '../components/Icon.astro';
       <WaitlistForm source="hero" id="waitlist" class="hero-form" />
 
       <p class="hero-secondary">
+        <a
+          href="https://demo.pcbjam.com"
+          class="try"
+          target="_blank"
+          rel="noopener"
+        >
+          Open the live editor →
+        </a>
+        <span class="dot" aria-hidden="true">·</span>
         <a href="#multiplayer" class="watch">
           <Icon name="icons/play.svg" size="1.1rem" alt="" /> Watch the 90-second demo →
         </a>
@@ -61,6 +70,19 @@ import Icon from '../components/Icon.astro';
   }
   .hero-secondary {
     margin: 1rem 0 0;
+    display: flex;
+    flex-wrap: wrap;
+    align-items: center;
+    gap: 0.4rem 0.75rem;
+  }
+  .try {
+    display: inline-flex;
+    align-items: center;
+    font-weight: 600;
+    color: var(--accent);
+  }
+  .dot {
+    color: var(--fg-muted);
   }
   .watch {
     display: inline-flex;