Tasks tab: NE Hub lists plus iCloud reminder lists where Apple exposes them

- Lists, quick add, due dates, notes, complete/reopen, delete; Home card for overdue/due today
- iCloud VTODO lists read and written over CalDAV (If-Match, edits patch the latest copy so
  priority/alarms survive); NE Hub lists work regardless
- Fix: text inside a nested VALARM was read as the task's / event's own description and then
  written back on edit; nested components are now skipped (regression tests added)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

public/style.css

@@ -232,3 +232,11 @@ textarea { padding: 12px 14px; resize: vertical; font-family: inherit; }
 
 /* Several kept-alive frames share #audiowrap; only the active one is shown (the others stay loaded, out of sight) */
 #audiowrap iframe:not(.act) { position: absolute; width: 1px; height: 1px; opacity: 0; pointer-events: none; border: 0; }
+
+/* Tasks */
+.tick { flex: none; color: var(--muted); }
+.tick svg { width: 26px; height: 26px; }
+.donetask .rmain b { text-decoration: line-through; color: var(--muted); }
+.donetask .tick { color: var(--accent); }
+.donetask .tick circle { fill: var(--accent); stroke: var(--accent); }
+.donetask .tick path { stroke: var(--accent-t); }