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>

Dockerfile

@@ -2,7 +2,7 @@ FROM node:22-alpine
 WORKDIR /app
 COPY package.json package-lock.json ./
 RUN npm ci --omit=dev
-COPY server.js auth.js cal.js ics.js caldav.js ./
+COPY server.js auth.js cal.js ics.js caldav.js tasks.js ./
 COPY public ./public
 ENV PORT=8080 DATA_DIR=/data
 RUN mkdir -p /data && chown node:node /data