feat(settings): unified Cloud Sync chooser with Readest Cloud as a first-class provider (#4976)

The Integrations section is now one Cloud Sync chooser: Readest Cloud,
WebDAV, and Google Drive as radio rows, Readest Cloud first, with a
scope subtitle stating what the choice governs (library data, on this
device) and what always stays with the Readest account (settings,
statistics, dictionaries).

- Activation helpers move to services (cloudSyncActivation.ts) and
  accept 'readest' (= no third-party provider active); the component
  module re-exports for existing imports.
- Row status lines come from a pure, fully-tested state matrix
  (cloudSyncStatus.ts) so every string is enumerated in one place:
  signed-out / loading / active / available for Readest Cloud;
  not connected / configured / paused / syncing / sync failed /
  book-file-uploads-off warning / active for third-party rows. The
  paused state renders on the affected third-party row (the plan sketch
  placed it on the Readest row; the provider that is paused is the
  third-party one).
- The Readest Cloud row opens an inline sub-page (SubPageHeader + the
  storage/translation Quota + a NavigationRow out to Account) instead of
  ejecting from the Settings dialog; signed-out taps go to login and the
  radio is unchecked and disabled, so an idle signed-out state never
  shows a checked radio while nothing syncs.
- Premium-gated builds keep the Readest Cloud row and show the upgrade
  prompt only in place of the third-party rows.
- Two-direction capability Tips in the WebDAV/Drive sub-pages spell out
  both what syncs only to the user's server and what still flows through
  the Readest account; the Upload Book Files description notes that
  Readest Cloud uploads pause while the provider is selected.
- Manage Sync book/progress/note rows swap their description to
  'Managed by {{provider}}...' via the existing locked-row pattern while
  a third-party provider is selected; the toggles stay interactive and
  persist since they govern the native channels after switch-back.
- The chooser rows form a radiogroup (native same-name radios provide
  arrow-key group movement) with an accessible group label.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

apps/readest-app/src/components/settings/integrations/cloudSync.ts

@@ -1,69 +1,10 @@
-import type { SystemSettings } from '@/types/settings';
-import type { EnvConfigType } from '@/services/environment';
-import type { FileSyncBackendKind } from '@/services/sync/file/providerRegistry';
-import { useSettingsStore } from '@/store/settingsStore';
-import { broadcastGlobalSettings } from '@/utils/settingsSync';
-
 /**
- * Return settings with exactly one third-party cloud-sync provider active (or
- * none). WebDAV and Google Drive are mutually exclusive — only one syncs the
- * library at a time — so enabling one always disables the other. Provider config
- * (WebDAV creds, the Drive keychain token) is left untouched, so switching back
- * to a previously-configured provider needs no re-entry; only an explicit
- * Disconnect tears a provider's config down.
- *
- * Activating a provider (disabled -> enabled) also turns its `syncBooks` on:
- * the selected provider owns the book-file channel — native Readest Cloud
- * uploads gate off — so leaving syncBooks at its `false` default would back
- * books up nowhere. An explicit opt-out while the provider stays active is
- * respected (re-activation of an already-active provider changes nothing).
+ * Re-export shim: the activation helpers moved to the services layer
+ * (`src/services/sync/cloudSyncActivation.ts`) so service modules never
+ * import from components. Existing component-side imports keep working.
  */
-export const withActiveCloudProvider = (
-  settings: SystemSettings,
-  active: FileSyncBackendKind | null,
-): SystemSettings => ({
-  ...settings,
-  webdav: {
-    ...settings.webdav,
-    enabled: active === 'webdav',
-    ...(active === 'webdav' && !settings.webdav?.enabled
-      ? { syncBooks: true, providerSelectedAt: Date.now() }
-      : {}),
-  },
-  googleDrive: {
-    ...settings.googleDrive,
-    enabled: active === 'gdrive',
-    ...(active === 'gdrive' && !settings.googleDrive?.enabled
-      ? { syncBooks: true, providerSelectedAt: Date.now() }
-      : {}),
-  },
-});
-
-/**
- * The single write path for changing the selected cloud sync provider.
- * Every activation/deactivation surface (the Integrations chooser, the
- * WebDAV/Drive connect and disconnect flows, the Drive OAuth callback)
- * routes through here so the change always (a) persists, (b) hydrates the
- * settings store even on routes where it wasn't loaded yet (the OAuth
- * callback), and (c) broadcasts the provider flags to other windows —
- * a stale reader window would otherwise clobber the switch on its next
- * whole-file save, silently resuming Readest Cloud uploads.
- *
- * `mutate` runs BEFORE activation so connect flows can apply credentials
- * or account labels without pre-setting `enabled` (which would suppress
- * the activation side effects).
- */
-export const persistActiveCloudProvider = async (
-  envConfig: EnvConfigType,
-  active: FileSyncBackendKind | null,
-  mutate: (settings: SystemSettings) => SystemSettings = (s) => s,
-): Promise<SystemSettings> => {
-  const store = useSettingsStore.getState();
-  const appService = await envConfig.getAppService();
-  const current = store.settings?.version ? store.settings : await appService.loadSettings();
-  const next = withActiveCloudProvider(mutate(current), active);
-  store.setSettings(next);
-  await appService.saveSettings(next);
-  void broadcastGlobalSettings(next, { includeCloudSyncProviders: true });
-  return next;
-};
+export {
+  withActiveCloudProvider,
+  persistActiveCloudProvider,
+  type CloudSyncActivationKind,
+} from '@/services/sync/cloudSyncActivation';