Index: scripts/migrate-posts-to-html.js
===================================================================
--- scripts/migrate-posts-to-html.js	(revision b5bae2470a5cdf5ae561708274d413dbf680523b)
+++ scripts/migrate-posts-to-html.js	(revision b5bae2470a5cdf5ae561708274d413dbf680523b)
@@ -0,0 +1,83 @@
+/**
+ * P58 — One-shot migration: convert markdown post.content to sanitized HTML.
+ *
+ * Run on the server AFTER deploying P58:
+ *   node scripts/migrate-posts-to-html.js
+ *
+ * Idempotent: posts whose content already starts with '<' are detected as
+ * HTML and skipped. Markdown posts are rendered via MarkdownService, then
+ * sanitized via HtmlSanitizerService, then written back. Original markdown
+ * is preserved in posts.content_legacy_md so we can roll back if needed.
+ *
+ * Re-running the script after the column is added is safe — the second run
+ * will see HTML content and skip everything.
+ */
+
+import db from '../src/config/database.js';
+import MarkdownService from '../src/services/MarkdownService.js';
+import HtmlSanitizerService from '../src/services/HtmlSanitizerService.js';
+
+function ensureBackupColumn() {
+  // Try to add the legacy_md backup column; SQLite throws if it exists.
+  try {
+    db.exec(`ALTER TABLE posts ADD COLUMN content_legacy_md TEXT`);
+    console.log('  + added posts.content_legacy_md column');
+  } catch (e) {
+    if (!/duplicate column/i.test(e.message)) throw e;
+  }
+}
+
+function looksLikeHtml(s) {
+  if (!s) return false;
+  // Heuristic: starts with a tag, OR contains common block-level tags. Doesn't
+  // need to be airtight — false positives just mean we skip a post that's
+  // already mostly HTML, which is fine.
+  const t = s.trimStart();
+  return t.startsWith('<') || /<\/?(p|h[1-6]|ul|ol|li|blockquote|figure|img|div)\b/i.test(s);
+}
+
+function migrateOne(post) {
+  if (!post.content || !post.content.trim()) {
+    return { id: post.id, action: 'empty' };
+  }
+  if (looksLikeHtml(post.content)) {
+    return { id: post.id, action: 'skipped-already-html' };
+  }
+  if (post.content_legacy_md) {
+    // Already migrated (legacy backup exists) but content somehow markdown again?
+    return { id: post.id, action: 'skipped-already-backed-up' };
+  }
+
+  const renderedHtml = MarkdownService.render(post.content);
+  const cleanHtml    = HtmlSanitizerService.sanitize(renderedHtml);
+
+  db.prepare(`
+    UPDATE posts SET content = ?, content_legacy_md = ?, updated_at = updated_at
+    WHERE id = ?
+  `).run(cleanHtml, post.content, post.id);
+
+  return { id: post.id, action: 'migrated', from: post.content.length, to: cleanHtml.length };
+}
+
+function main() {
+  console.log('PrutFolio P58 — markdown → HTML post migration\n');
+  ensureBackupColumn();
+
+  const posts = db.prepare(`SELECT id, slug, content, content_legacy_md FROM posts`).all();
+  console.log(`  found ${posts.length} posts\n`);
+
+  const stats = { migrated: 0, skipped: 0, empty: 0 };
+  for (const p of posts) {
+    const r = migrateOne(p);
+    const tag = r.action.startsWith('skipped') ? 'skipped' :
+                r.action === 'empty' ? 'empty' : 'migrated';
+    stats[tag]++;
+    const detail = r.action === 'migrated' ? ` (${r.from} md → ${r.to} html chars)` : ` [${r.action}]`;
+    console.log(`  - ${p.slug}${detail}`);
+  }
+
+  console.log(`\nDone. migrated=${stats.migrated}  skipped=${stats.skipped}  empty=${stats.empty}`);
+  console.log('Backup column posts.content_legacy_md retains original markdown.');
+}
+
+main();