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-ko/strings.xml

@@ -581,6 +581,9 @@
     <string name="cron_edit_field_script">스크립트</string>
     <string name="cron_edit_field_workdir">작업 디렉토리</string>
     <string name="cron_edit_field_no_agent">에이전트 없음 (스크립트 전용)</string>
+    <string name="cron_edit_field_run_continuity">실행 연속성</string>
+    <string name="cron_edit_hint_run_continuity">이 작업의 이전 출력을 매 실행에 주입</string>
+    <string name="cron_badge_continuity">연속</string>
     <string name="cron_edit_hint_schedule">예: 0 9 * * * 또는 every 2h</string>
     <string name="cron_edit_hint_deliver">예: origin, local, all, 또는 telegram:chat_id</string>
     <string name="cron_edit_hint_skills">한 줄에 하나씩</string>