Gate Issue #4 until publication date (Apr 13)

- Move #4 from live pattern grid to Coming Soon on index.html
- Remove #4 from nav bar (index.html and interactive.js NAV_ISSUES)
- Interactive page files remain in repo, ready to un-gate on pub day

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: justinpreston

index.html

@@ -205,7 +205,6 @@
     <a class="nav-issue-link" href="interactive/issue-001/index.html">#001 Code-First</a>
     <a class="nav-issue-link" href="interactive/issue-002/index.html">#002 Scoped Search</a>
     <a class="nav-issue-link" href="interactive/issue-003/index.html">#003 Prompt Chain</a>
-    <a class="nav-issue-link" href="interactive/issue-004/index.html">#004 In-Boundary</a>
   </div>
 </nav>
 
@@ -275,26 +274,19 @@ <h1>The Cheat Code</h1>
       </div>
     </a>
 
-    <a class="pattern-card" href="interactive/issue-004/index.html">
+  </div>
+
+  <!-- COMING NEXT -->
+  <div class="section-label">Coming Soon</div>
+  <div class="pattern-grid">
+    <div class="pattern-card coming-soon">
       <div class="card-header">
         <span class="card-num">#004</span>
         <span class="card-builder">Raghav BN</span>
       </div>
       <div class="card-title">Secure In-Boundary Processing</div>
       <div class="card-desc">"Our data can't leave our tenant." MCP connectors + in-memory aggregation + tenant-scoped AI. The architecture for regulated industries.</div>
-      <div class="card-cta">🔬 Explore interactively →</div>
-      <div class="card-tags">
-        <span class="tag tag-green">Compliance</span>
-        <span class="tag tag-blue">MCP</span>
-        <span class="tag tag-orange">In-Boundary</span>
-      </div>
-    </a>
-
-  </div>
-
-  <!-- COMING NEXT -->
-  <div class="section-label">Coming Soon</div>
-  <div class="pattern-grid">
+    </div>
     <div class="pattern-card coming-soon">
       <div class="card-header">
         <span class="card-num">#005</span>

interactive/shared/interactive.js

@@ -329,7 +329,6 @@
     { num: '001', short: '#001', title: 'Code-First Delivery', path: '../issue-001/index.html' },
     { num: '002', short: '#002', title: 'Multi-Source Search', path: '../issue-002/index.html' },
     { num: '003', short: '#003', title: 'Prompt-Chained Triage', path: '../issue-003/index.html' },
-    { num: '004', short: '#004', title: 'Secure In-Boundary', path: '../issue-004/index.html' },
   ];
 
   function buildGlobalNav() {