feat: website templating system — shared nav/footer partials, build-time HTML assembly

- Build script: scripts/build-pages.js (zero dependencies, Node.js only)
- Shared partials: nav.html, footer.html (single source of truth)
- 5 page templates in templates/pages/
- Output is byte-for-byte identical to current production
- Run: npm run build:pages
- Also fixes JSON-LD: 2,500 → 5,000 PDFs/month (was inconsistent)

scripts/build-pages.js

@@ -0,0 +1,75 @@
+#!/usr/bin/env node
+/**
+ * Build-time HTML templating system for DocFast.
+ * No dependencies — uses only Node.js built-ins.
+ *
+ * - Reads page sources from templates/pages/*.html
+ * - Reads partials from templates/partials/*.html
+ * - Replaces {{> partial_name}} with partial content
+ * - Supports <!-- key: value --> metadata comments at top of page files
+ * - Replaces {{key}} variables with extracted metadata
+ * - Writes output to public/
+ */
+
+import { readFileSync, writeFileSync, readdirSync } from 'node:fs';
+import { join } from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const __dirname = fileURLToPath(new URL('.', import.meta.url));
+const ROOT = join(__dirname, '..');
+const PAGES_DIR = join(ROOT, 'templates', 'pages');
+const PARTIALS_DIR = join(ROOT, 'templates', 'partials');
+const OUTPUT_DIR = join(ROOT, 'public');
+
+// Load all partials
+const partials = {};
+for (const file of readdirSync(PARTIALS_DIR)) {
+  if (!file.endsWith('.html')) continue;
+  const name = file.replace('.html', '');
+  partials[name] = readFileSync(join(PARTIALS_DIR, file), 'utf-8');
+}
+
+console.log(`Loaded ${Object.keys(partials).length} partials: ${Object.keys(partials).join(', ')}`);
+
+// Process each page
+const pages = readdirSync(PAGES_DIR).filter(f => f.endsWith('.html'));
+console.log(`Processing ${pages.length} pages...`);
+
+for (const file of pages) {
+  let content = readFileSync(join(PAGES_DIR, file), 'utf-8');
+
+  // Extract all <!-- key: value --> metadata comments from the top
+  const vars = {};
+  while (true) {
+    const m = content.match(/^<!--\s*([a-zA-Z_-]+):\s*(.+?)\s*-->\n?/);
+    if (!m) break;
+    vars[m[1]] = m[2];
+    content = content.slice(m[0].length);
+  }
+
+  // Replace {{> partial_name}} with partial content (support nested partials)
+  let maxDepth = 5;
+  while (maxDepth-- > 0 && content.includes('{{>')) {
+    content = content.replace(/\{\{>\s*([a-zA-Z0-9_-]+)\s*\}\}/g, (match, name) => {
+      if (!(name in partials)) {
+        console.warn(`  Warning: partial "${name}" not found in ${file}`);
+        return match;
+      }
+      return partials[name];
+    });
+  }
+
+  // Replace {{variable}} with extracted metadata
+  content = content.replace(/\{\{([a-zA-Z_-]+)\}\}/g, (match, key) => {
+    if (key in vars) return vars[key];
+    console.warn(`  Warning: variable "${key}" not defined in ${file}`);
+    return match;
+  });
+
+  // Write output
+  const outPath = join(OUTPUT_DIR, file);
+  writeFileSync(outPath, content);
+  console.log(`  ✓ ${file} (${(content.length / 1024).toFixed(1)}KB)`);
+}
+
+console.log('Done!');