site(landing): demo-first CTAs, light theme, honest copy; restore positioning map

Now that demo.pcbjam.com is live, the landing page leads with it instead
of "coming soon":

- Hero: "Open the live demo" is the primary CTA; the coming-soon panel is
  replaced by a DemoLaunchCard (screenshot + play overlay, new tab — the
  editor needs COOP/COEP so it can never be iframed here); waitlist demoted
  to a ghost button under a "Want early access to multiplayer?" lead-in.
- Removed the Gerber demo and positioning-map sections, then restored the
  positioning map per review — recolored for light theme and without the
  multiplayer badge/legend ("Everyone picks one. We do both.").
- Light theme: flipped the :root ink tokens, darkened accent/signal for
  contrast on white; fixed two dark-assumption bugs it exposed (header CTA
  text losing to .nav>a specificity, DemoVideo play scrim derived from --bg).
- Copy: positioned around what's live (real KiCad in a tab) with
  multiplayer explicitly "coming — join the waitlist"; cut untrue claims
  (GitHub import, self-host, offline PWA -> roadmap); cut the jam metaphor
  outside the product name; TrustBar fake-stat grid -> plain claims strip;
  footer tagline + fallback meta description aligned.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01REwWZGkAz1AZUJw8yqxkCN

site/public/graphics/positioning-quadrant.svg

@@ -1,15 +1,15 @@
 <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 820 600" width="820" height="600" role="img" aria-labelledby="pq-title pq-desc" font-family="system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif">
   <title id="pq-title">PCB tool positioning map</title>
-  <desc id="pq-desc">A quadrant chart. The horizontal axis runs from desktop-install on the left to browser-native on the right; the vertical axis from proprietary at the bottom to open at the top. LibrePCB and KiCad sit top-left (open but desktop). KiCanvas sits top-right but is viewer-only. Flux and EasyEDA sit bottom-right (browser but proprietary). Altium 365 and OrCAD X sit bottom-left (desktop and proprietary). PCBJam sits alone in the top-right as the only browser-native, open, real-time-multiplayer tool.</desc>
+  <desc id="pq-desc">A quadrant chart. The horizontal axis runs from desktop-install on the left to browser-native on the right; the vertical axis from proprietary at the bottom to open at the top. LibrePCB and KiCad sit top-left (open but desktop). KiCanvas sits top-right but is viewer-only. Flux and EasyEDA sit bottom-right (browser but proprietary). Altium 365 and OrCAD X sit bottom-left (desktop and proprietary). PCBJam sits alone in the top-right as the only full editor that is both browser-native and open.</desc>
 
   <!-- panel -->
-  <rect x="8" y="8" width="804" height="584" rx="16" fill="#11182e" stroke="#233052" stroke-width="1"/>
+  <rect x="8" y="8" width="804" height="584" rx="16" fill="#f4f7fc" stroke="#d9e1f0" stroke-width="1"/>
 
   <!-- top-right "whitespace" tint -->
   <rect x="410" y="64" width="338" height="232" fill="#4f7cff" fill-opacity="0.09"/>
 
   <!-- axes -->
-  <g stroke="#34436b" stroke-width="2" fill="#34436b">
+  <g stroke="#aebad2" stroke-width="2" fill="#aebad2">
     <line x1="80" y1="296" x2="748" y2="296"/>
     <line x1="410" y1="64" x2="410" y2="528"/>
     <polygon points="748,296 734,289 734,303" stroke="none"/>
@@ -19,7 +19,7 @@
   </g>
 
   <!-- axis labels -->
-  <g fill="#9aa6c0" font-size="14" font-weight="600">
+  <g fill="#5b6784" font-size="14" font-weight="600">
     <text x="410" y="50" text-anchor="middle">Open &amp; yours</text>
     <text x="410" y="554" text-anchor="middle">Proprietary, locked-in</text>
     <text x="92" y="316" text-anchor="start">Desktop install</text>
@@ -27,7 +27,7 @@
   </g>
 
   <!-- competitors -->
-  <g fill="#8794ad">
+  <g fill="#8b98b3">
     <circle cx="210" cy="150" r="5"/>
     <circle cx="250" cy="205" r="5"/>
     <circle cx="540" cy="200" r="5"/>
@@ -36,7 +36,7 @@
     <circle cx="210" cy="388" r="5"/>
     <circle cx="250" cy="448" r="5"/>
   </g>
-  <g fill="#b4bfd6" font-size="15">
+  <g fill="#3d4a68" font-size="15">
     <text x="224" y="155">LibrePCB</text>
     <text x="264" y="210">KiCad</text>
     <text x="554" y="205">KiCanvas</text>
@@ -45,16 +45,10 @@
     <text x="224" y="393">Altium 365</text>
     <text x="264" y="453">OrCAD X</text>
   </g>
-  <text x="554" y="222" font-size="11" fill="#6b7796">viewer only</text>
+  <text x="554" y="222" font-size="11" fill="#8b98b3">viewer only</text>
 
-  <!-- PCBJam marker (the only "all three") -->
+  <!-- PCBJam marker (the only browser-native + open editor) -->
   <circle cx="590" cy="120" r="30" fill="#4f7cff" fill-opacity="0.12"/>
-  <text x="590" y="130" text-anchor="middle" font-size="30" fill="#32d583">★</text>
-  <text x="614" y="128" text-anchor="start" font-size="19" font-weight="700" fill="#e7ecf5">PCBJam</text>
-  <rect x="560" y="140" width="170" height="24" rx="12" fill="#32d583" fill-opacity="0.15" stroke="#32d583" stroke-opacity="0.6"/>
-  <text x="645" y="156" text-anchor="middle" font-size="12" fill="#32d583" font-family="ui-monospace, SFMono-Regular, Menlo, Consolas, monospace">real-time multiplayer</text>
-
-  <!-- legend -->
-  <text x="34" y="580" font-size="14" fill="#32d583">★</text>
-  <text x="50" y="580" font-size="12" fill="#9aa6c0">= true real-time multiplayer (PCBJam only)</text>
+  <text x="590" y="130" text-anchor="middle" font-size="30" fill="#2f57f5">★</text>
+  <text x="614" y="128" text-anchor="start" font-size="19" font-weight="700" fill="#101729">PCBJam</text>
 </svg>