feat(site): add version badge to navbar with auto-update on release

Display version number and release date (e.g., "v0.1.8 · Feb 7, 2026")
next to the "Under Construction" badge in the top nav bar. Version and
date are declared as top-of-file constants in wip-banner.js for easy
CI sed updates. Publish workflow now bumps 6 files instead of 5.

.github/workflows/tinytorch-publish-live.yml

@@ -17,9 +17,10 @@ name: '🔥 TinyTorch · 🚀 Publish (Live)'
 #      └─ Run tinytorch-validate-dev.yml tests
 #
 #   3. update-version (if preflight passes) [SKIPPED if site_only=true]
-#      └─ Bump version in 5 files on dev branch:
+#      └─ Bump version in 6 files on dev branch:
 #         - pyproject.toml (single source of truth - __init__.py reads from this)
 #         - site/_static/version-badge.js
+#         - site/_static/wip-banner.js (navbar version badge)
 #         - site/extra/install.sh
 #         - site/_static/announcement.json
 #         - README.md
@@ -232,6 +233,21 @@ jobs:
           echo "✅ version-badge.js updated"
           cat tinytorch/site/_static/version-badge.js | grep "const version"
 
+      - name: 📝 Update version in navbar badge
+        run: |
+          echo "📝 Updating version in tinytorch/site/_static/wip-banner.js..."
+
+          VERSION_NUM="${{ needs.validate-inputs.outputs.new_version }}"
+          VERSION_NUM=${VERSION_NUM#tinytorch-v}
+          RELEASE_DATE=$(date +'%b %-d, %Y')
+
+          # Update the top-of-file constants (easy to find, easy to sed)
+          sed -i "s/const TINYTORCH_VERSION = '.*'/const TINYTORCH_VERSION = '$VERSION_NUM'/" tinytorch/site/_static/wip-banner.js
+          sed -i "s/const TINYTORCH_RELEASE_DATE = '.*'/const TINYTORCH_RELEASE_DATE = '$RELEASE_DATE'/" tinytorch/site/_static/wip-banner.js
+
+          echo "✅ wip-banner.js updated"
+          head -10 tinytorch/site/_static/wip-banner.js
+
       - name: 📝 Update version in installer
         run: |
           echo "📝 Updating version in tinytorch/site/extra/install.sh..."
@@ -290,7 +306,7 @@ jobs:
           git config user.name "github-actions[bot]"
           git config user.email "github-actions[bot]@users.noreply.github.com"
 
-          git add tinytorch/pyproject.toml tinytorch/site/_static/version-badge.js tinytorch/site/extra/install.sh tinytorch/site/_static/announcement.json tinytorch/README.md
+          git add tinytorch/pyproject.toml tinytorch/site/_static/version-badge.js tinytorch/site/_static/wip-banner.js tinytorch/site/extra/install.sh tinytorch/site/_static/announcement.json tinytorch/README.md
           git commit -m "chore(tinytorch): bump version to ${{ needs.validate-inputs.outputs.new_version }}" || echo "No changes to commit"
           git push origin dev
 

tinytorch/site/_static/custom.css

@@ -410,6 +410,26 @@ pre.mermaid {
     letter-spacing: 0.02em;
 }
 
+.tinytorch-bar-version {
+    font-size: 0.75rem;
+    font-weight: 500;
+    color: #9ca3af;
+    background: rgba(156, 163, 175, 0.1);
+    padding: 0.3rem 0.75rem;
+    border-radius: 4px;
+    border: 1px solid rgba(156, 163, 175, 0.2);
+    text-decoration: none;
+    font-family: 'SF Mono', 'Fira Code', 'Fira Mono', 'Roboto Mono', monospace;
+    letter-spacing: 0.01em;
+    transition: all 0.15s ease;
+}
+
+.tinytorch-bar-version:hover {
+    color: #e5e7eb;
+    background: rgba(156, 163, 175, 0.18);
+    border-color: rgba(156, 163, 175, 0.35);
+}
+
 .tinytorch-bar-links {
     display: flex;
     align-items: center;
@@ -483,6 +503,10 @@ pre.mermaid {
         display: none;
     }
 
+    .tinytorch-bar-version {
+        display: none;
+    }
+
     .tinytorch-bar-left {
         gap: 0.5rem;
     }

tinytorch/site/_static/wip-banner.js

@@ -3,6 +3,11 @@
  * Elegant navigation bar matching MLSysBook style
  */
 
+// ── Release info (auto-updated by CI on publish) ──────────────
+const TINYTORCH_VERSION = '0.1.8';
+const TINYTORCH_RELEASE_DATE = 'Feb 7, 2026';
+// ───────────────────────────────────────────────────────────────
+
 document.addEventListener('DOMContentLoaded', function() {
     // Only inject if not already present
     if (document.getElementById('tinytorch-bar')) return;
@@ -28,6 +33,7 @@ document.addEventListener('DOMContentLoaded', function() {
                         Tiny<span class="brand-fire">🔥</span>Torch
                     </a>
                     <span class="tinytorch-bar-badge">Under Construction</span>
+                    <a href="https://github.com/harvard-edge/cs249r_book/releases" target="_blank" rel="noopener noreferrer" class="tinytorch-bar-version" title="View releases on GitHub">v${TINYTORCH_VERSION} · ${TINYTORCH_RELEASE_DATE}</a>
                 </div>
                 <div class="tinytorch-bar-links">
                     <a href="${siteRoot}_static/downloads/TinyTorch-Guide.pdf" class="download-link" title="Download Course Guide (PDF)">