feat(cron): monitor-mode jobs (monitor_script/monitor_url) + blocked_config status (issue #861) (#871)

- CronJob model gains optional monitor_script/monitor_url (additive-safe)
- Job editor: Monitor mode section (off/script/url) with XOR source clearing;
  disabled while no-agent is set (backend invariant); new jobs apply monitor
  via create -> follow-up PUT with rollback delete on failure (the REST create
  model drops the fields)
- Job list/details: blocked_config renders as a distinct error badge
  ('Blocked (config)'), no_change as informational; monitor source shown in
  run details

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

app/src/main/java/com/m57/hermescontrol/data/model/CronJob.kt

@@ -38,6 +38,10 @@ data class CronJob(
     val workdir: String? = null,
     val no_agent: Boolean? = null,
     val repeat: CronJobRepeat? = null,
+    // Monitor-mode jobs (backend cron/monitor.py): a source script/URL whose
+    // output is hashed each tick — the agent runs only when it changes.
+    val monitor_script: String? = null,
+    val monitor_url: String? = null,
 ) {
     val scheduleText: String
         get() =
@@ -52,4 +56,8 @@ data class CronJob(
 
     val nextRunTime: String
         get() = next_run ?: next_run_at ?: ""
+
+    /** The configured monitor source (script or URL), if any. */
+    val monitorSource: String?
+        get() = monitor_script ?: monitor_url
 }

app/src/main/java/com/m57/hermescontrol/data/model/CronJobRequests.kt

@@ -18,6 +18,11 @@ data class CreateCronJobRequest(
     val workdir: String? = null,
     val no_agent: Boolean = false,
     val repeat: Int? = null,
+    // Monitor mode. NOTE: the backend REST create model does not carry these
+    // yet (they are silently dropped on POST) — the ViewModel applies them
+    // via a follow-up PUT; keep them here for forward compatibility.
+    val monitor_script: String? = null,
+    val monitor_url: String? = null,
 )
 
 @Serializable