Golden gate: Linux baselines, canonical save, gate hardening (D521-D532)

Linux reference-frame set for all 21 levels and the cross-platform golden
rule (D521); golden tooling made non-destructive (D524); the gate pins a
canonical in-tree save (D529) and the PRNG seed (D532); the capture tool's
per-level re-pin bug fixed and the Linux set re-captured under the
canonical save (D530, D531); no-arg verify.sh exits non-zero. README and
docs visual/consolidation passes; the 15 MB preview gif replaced by stills.

Refs: D521 D523 D524 D525 D526 D527 D528 D529 D530 D531 D532

docs/_layouts/default.html

@@ -3,46 +3,44 @@
 <head>
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
-  <link rel="icon" type="image/png" href="{{ '/img/attract-bunker1.png' | relative_url }}">
+  <link rel="icon" type="image/jpeg" href="{{ '/img/shots/shot-28.jpg' | relative_url }}">
   {%- seo -%}
   {%- include head-custom.html -%}
 </head>
 <body>
-  <header class="site-masthead">
-    <div class="masthead-inner">
-      <a class="masthead-title" href="{{ '/' | relative_url }}">{{ site.title }}</a>
-      <div class="masthead-tagline">{{ site.description }}</div>
-      <nav class="masthead-nav">
-        <a href="{{ '/' | relative_url }}">Home</a><span class="nav-sep">·</span>
-        <a href="{{ '/internals' | relative_url }}">Internals</a><span class="nav-sep">·</span>
-        <a href="{{ '/porting-notes' | relative_url }}">Porting notes</a><span class="nav-sep">·</span>
-        <a href="{{ '/building' | relative_url }}">Building</a><span class="nav-sep">·</span>
-        <a href="{{ '/dev-process' | relative_url }}">Dev process</a><span class="nav-sep">·</span>
-        <a href="{{ '/dev/agentic-development' | relative_url }}">Two-agent study</a>
-      </nav>
-    </div>
-  </header>
+  <div class="frame">
 
-  <main class="doc-content">
-    {{ content }}
-  </main>
+    <header class="banner">
+      <div class="t">{{ site.title }}</div>
+      <div class="tag">{{ site.description }}</div>
+    </header>
 
-  <footer class="site-footer">
-    <div class="footer-inner">
-      <p class="footer-stamp">
-        Last updated 2026-09-28 — v0.4.0
-        <span class="nav-sep">·</span>
-        <a href="https://github.com/jkdansereau/goldeneye-pc-port">GitHub</a>
-        <span class="nav-sep">·</span>
-        <a href="https://github.com/jkdansereau/goldeneye-pc-port/releases">Releases</a>
-      </p>
-      <p class="footer-legal">
-        Non-commercial fan preservation/research project. No ROM or game assets
-        are distributed; you supply a ROM you already own. Not affiliated with
-        or endorsed by Nintendo, Rare, Microsoft, MGM, Danjaq, or EON
-        Productions.
-      </p>
-    </div>
-  </footer>
+    <nav class="sitenav">
+      <a href="{{ '/' | relative_url }}">home</a><span class="sep">/</span>
+      <a href="{{ '/under-the-hood' | relative_url }}">under the hood</a><span class="sep">/</span>
+      <a href="{{ '/building' | relative_url }}">building</a>
+    </nav>
+    <div class="rule g"></div>
+
+    <main class="doc-content">
+      {{ content }}
+    </main>
+
+    <div class="rule g"></div>
+
+    <footer class="site-footer">
+      <div class="footer-stamp">
+        last updated: 2026-10-07 &middot; v0.5.0
+        &nbsp;&middot;&nbsp; <a href="https://github.com/jkdansereau/goldeneye-pc-port">GitHub</a>
+        &nbsp;&middot;&nbsp; <a href="https://github.com/jkdansereau/goldeneye-pc-port/releases">releases</a>
+      </div>
+      <div class="footer-legal">
+        Non-commercial fan preservation / research project. No ROM or game assets are
+        distributed; you supply a ROM you already own. Not affiliated with or endorsed
+        by Nintendo, Rare, Microsoft, MGM, Danjaq, or EON Productions.
+      </div>
+    </footer>
+
+  </div>
 </body>
 </html>