feat(plane): add Plane-TODO sync script

Add plane-sync.js one-way (Plane -> TODO.md) synchronization for the
MITHOME project. Config reads from .mcp.json with .env override. CLI:
--list, --dry-run, --yes, --project, --verbose, --help. Interactive
discrepancy resolution (status mismatches, orphans, new issues), backup
before write, rate limiting. Pure functions covered by node:test unit
tests. Includes PLANE-SYNC-GUIDE.md and TODO.md changelog entry.

scripts/plane/todo.js

@@ -0,0 +1,101 @@
+// WHY: sections are identified by emoji header; order defines generated layout
+const SECTIONS = [
+  { key: 'completed', header: /^## ✅/, emoji: '✅', hasNote: false },
+  { key: 'todo', header: /^## 🚀/, emoji: '⏳', hasNote: true },
+  { key: 'inProgress', header: /^## 🔄/, emoji: '🔄', hasNote: true },
+  { key: 'backlog', header: /^## 📋/, emoji: '📋', hasNote: false }
+];
+
+const SECTION_LABEL = {
+  completed: 'Befejezett',
+  todo: 'TODO',
+  inProgress: 'In Progress',
+  backlog: 'Backlog'
+};
+
+function parseTodoFile(content) {
+  const sections = {
+    completed: { header: null, rows: [] },
+    todo: { header: null, rows: [] },
+    inProgress: { header: null, rows: [] },
+    backlog: { header: null, rows: [] }
+  };
+  const rows = [];
+  let current = null;
+
+  for (const line of content.split('\n')) {
+    const sec = SECTIONS.find(s => s.header.test(line));
+    if (sec) {
+      current = sec.key;
+      if (!sections[current].header) sections[current].header = line;
+      continue;
+    }
+    if (!current || !line.trim().startsWith('|')) continue;
+    const cols = line.split('|').map(c => c.trim()).filter(c => c !== '');
+    if (cols.length < 3) continue;
+    if (cols[0] === 'Plane' || /^[-]+$/.test(cols[0])) continue;
+    const row = { id: cols[0], name: cols[1], status: cols[2], note: cols[3] || '' };
+    sections[current].rows.push(row);
+    rows.push({ section: current, ...row });
+  }
+
+  return { sections, rows };
+}
+
+function seqNum(id) {
+  const match = id.match(/(\d+)$/);
+  return match ? parseInt(match[1], 10) : 0;
+}
+
+function buildTable(sec, rows) {
+  const header = sec.hasNote
+    ? '| Plane | Feladat | Státusz | Megjegyzés |'
+    : '| Plane | Feladat | Státusz |';
+  const separator = sec.hasNote
+    ? '|-------|---------|---------|-----------|'
+    : '|-------|---------|---------|';
+  const body = rows
+    .slice()
+    .sort((a, b) => seqNum(a.id) - seqNum(b.id))
+    .map(row => {
+      if (sec.hasNote) return `| ${row.id} | ${row.name} | ${sec.emoji} | ${row.note || ''} |`;
+      return `| ${row.id} | ${row.name} | ${sec.emoji} |`;
+    });
+  return [header, separator, ...body].join('\n');
+}
+
+// WHY: only the section region is regenerated, prefix/suffix (overview, commands) are preserved
+function regenerate(content, finalSections) {
+  const lines = content.split('\n');
+  const firstIdx = lines.findIndex(l => SECTIONS[0].header.test(l));
+  const backlogIdx = lines.findIndex(l => SECTIONS[3].header.test(l));
+  if (firstIdx === -1 || backlogIdx === -1) throw new Error('TODO.md section headers not found');
+
+  let endIdx = lines.length;
+  for (let i = backlogIdx + 1; i < lines.length; i++) {
+    if (lines[i].trim() === '---') {
+      endIdx = i;
+      break;
+    }
+  }
+
+  const prefix = lines.slice(0, firstIdx).join('\n');
+  const suffix = lines.slice(endIdx + 1).join('\n');
+
+  const headerOf = key => {
+    const sec = SECTIONS.find(s => s.key === key);
+    const idx = lines.findIndex(l => sec.header.test(l));
+    return idx >= 0 ? lines[idx].replace(/^## /, '') : key;
+  };
+
+  const blocks = SECTIONS.map(sec => {
+    const rows = finalSections[sec.key] || [];
+    return `## ${headerOf(sec.key)}\n\n${buildTable(sec, rows)}`;
+  });
+  const middle = blocks.join('\n\n---\n\n') + '\n\n---\n';
+
+  const result = `${prefix}${middle}${suffix}`;
+  return result.endsWith('\n') ? result : `${result}\n`;
+}
+
+module.exports = { SECTIONS, SECTION_LABEL, parseTodoFile, buildTable, regenerate, seqNum };