feat(cron): register cron page in router + sidebar, fix Gateway RPC call formats

- main.js: register /cron route
- sidebar.js: add '定时任务' to '数据' section
- cron.js: fix RPC params to match Gateway API:
  - cron.list: add includeDisabled param
  - cron.add: use structured schedule{kind,expr} + payload{kind,message}
  - cron.update: use patch format
  - cron.run: add mode:'force'
  - Map Gateway CronJob state fields (lastRunStatus, lastRunAtMs, etc)

src/main.js

@@ -304,6 +304,7 @@ async function boot() {
   registerRoute('/setup', () => import('./pages/setup.js'))
   registerRoute('/docker', () => import('./pages/docker.js'))
   registerRoute('/channels', () => import('./pages/channels.js'))
+  registerRoute('/cron', () => import('./pages/cron.js'))
 
   renderSidebar(sidebar)
   initRouter(content)