feat(cron): add Run Continuity toggle + badge (#924) (#932)

Expose backend cron self-continuity (context_from=["self"]) in the Cron
editor. Adds a Run Continuity checkbox to the job editor that sends
context_from=["self"] on create and update (null when off, clearing it),
prefills from the loaded job's context_from, and shows a "Continuity" badge
on recurring jobs in the list. context_from was already on CronJob and
CreateCronJobRequest, so this is editor/list wiring only. Strings added for
en/zh/ko. Includes two ViewModel tests.

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/res/values/strings.xml

@@ -826,6 +826,9 @@
     <string name="cron_edit_field_script">Script</string>
     <string name="cron_edit_field_workdir">Work Directory</string>
     <string name="cron_edit_field_no_agent">No agent (script-only)</string>
+    <string name="cron_edit_field_run_continuity">Run continuity</string>
+    <string name="cron_edit_hint_run_continuity">Inject this job\'s previous output into each run</string>
+    <string name="cron_badge_continuity">Continuity</string>
     <string name="cron_edit_monitor_mode">Monitor mode</string>
     <string name="cron_edit_monitor_off">Off</string>
     <string name="cron_edit_monitor_script">Script</string>