fixes: collab move, caldav abort, draft recovery, autobackup, test stabilization

- Collab: moving a shared card to a local bucket no longer deletes it
  (clear relay_uid before tombstone echo returns)
- CalDAV: abort sync on remote fetch failure instead of treating all
  local cards as remotely-deleted
- Editor: autobackup drafts to localStorage with restore prompt on
  re-open (skipped during tests)
- Cards POST: persist scratchpad and due_date (was dropped on create)
- Disable spellcheck/autocorrect on editor inputs
- Test runner: purge leftover __prefix__ cards/buckets + editor drafts
  before every run (cleans up from failed previous runs)
- Stabilize mark-done, group-delete, undo-body tests with poll loops

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

public/plugins/tests/runner.js

@@ -201,6 +201,37 @@ async function createBackup() {
     backupBlob = await res.blob();
 }
 
+// Purge leftover test artifacts from previous failed runs.
+// Tests use `__prefix__` naming; anything matching gets deleted before
+// the baseline backup so it doesn't get restored after the run either.
+async function purgeTestLeftovers() {
+    const token = () => document.cookie.match(/csrf=([^;]+)/)?.[1] || getCsrf();
+    let purged = { cards: 0, buckets: 0 };
+    try {
+        const cards = await fetch('api/cards').then(r => r.json());
+        const testCards = cards.filter(c => /^__.*__/.test(c.title || ''));
+        for (const c of testCards) {
+            await fetch(`api/cards/${c.id}`, { method: 'DELETE', headers: { 'X-CSRF-Token': token() } });
+            purged.cards++;
+        }
+    } catch {}
+    try {
+        const buckets = await fetch('api/buckets').then(r => r.json());
+        const testBuckets = buckets.filter(b => /^__.*__/.test(b.name || ''));
+        for (const b of testBuckets) {
+            await fetch(`api/buckets/${b.id}`, { method: 'DELETE', headers: { 'X-CSRF-Token': token() } });
+            purged.buckets++;
+        }
+    } catch {}
+    // Also clear any leftover editor drafts so the restore prompt doesn't fire
+    try {
+        for (const k of Object.keys(localStorage)) {
+            if (k.startsWith('hyprcrd-editor-draft')) localStorage.removeItem(k);
+        }
+    } catch {}
+    return purged;
+}
+
 async function restoreBackup() {
     if (!backupBlob) return;
     const form = new FormData();
@@ -398,10 +429,18 @@ async function run() {
     const output = panel.querySelector('#test-output');
     const summary = panel.querySelector('#test-summary');
 
-    // 1. Create backup
-    output.innerHTML = '<div style="color:#64748b;">creating backup...</div>';
+    // 1. Purge leftover test artifacts from any previous failed run
+    output.innerHTML = '<div style="color:#64748b;">cleaning up previous test artifacts...</div>';
     summary.textContent = '';
     await sleep(50);
+    const purged = await purgeTestLeftovers();
+    if (purged.cards || purged.buckets) {
+        output.innerHTML += `<div style="color:#fbbf24;">purged ${purged.cards} leftover card${purged.cards !== 1 ? 's' : ''}, ${purged.buckets} bucket${purged.buckets !== 1 ? 's' : ''}</div>`;
+    }
+
+    // 2. Create backup (clean baseline)
+    output.innerHTML += '<div style="color:#64748b;">creating backup...</div>';
+    await sleep(50);
     try {
         await createBackup();
     } catch (e) {