Hide inactive boards, keep source and target stack apart, make the interval configurable

- Boards: BoardService::getUserBoards() defaults to $includeArchived = true,
  and that flag also gates the `deleted_at = 0` condition, so archived and
  trashed boards showed up in the dropdown. Request the filtered query
  instead, with a fallback to the no-arg call if the signature ever changes.
  Stacks need nothing: StackMapper::findAll() always filters deleted_at.
- Each stack dropdown now hides whatever the other one holds, so source and
  target can no longer be set to the same stack. The save-time check stays
  as the backstop for rows stored before this rule.
- RunWorkflowsJob reads its interval from config.php
  ('workflow_deck_automation.interval', seconds, default 300, clamped to a
  60s minimum). TimedJob re-reads the interval on every cron pass, so a
  changed value takes effect without any occ command.

src/PersonalSettings.vue

@@ -74,7 +74,7 @@
 				<NcSelect
 					v-model="form.sourceStackId"
 					input-label="Quell-Stapel"
-					:options="stackOptions"
+					:options="sourceStackOptions"
 					:reduce="option => option.value"
 					:disabled="!form.boardId"
 					placeholder="Quell-Stapel wählen" />
@@ -82,7 +82,7 @@
 				<NcSelect
 					v-model="form.targetStackId"
 					input-label="Ziel-Stapel"
-					:options="stackOptions"
+					:options="targetStackOptions"
 					:reduce="option => option.value"
 					:disabled="!form.boardId"
 					placeholder="Ziel-Stapel wählen" />
@@ -167,6 +167,12 @@ const participantOptions = ref([])
 
 const boardOptions = computed(() => boards.value.map((board) => ({ value: board.id, label: board.title })))
 
+// Source and target must differ, so each dropdown hides what the other one
+// already holds — the error message on save stays as the backstop for
+// workflows stored before this rule existed.
+const sourceStackOptions = computed(() => stackOptions.value.filter((option) => option.value !== form.targetStackId))
+const targetStackOptions = computed(() => stackOptions.value.filter((option) => option.value !== form.sourceStackId))
+
 const form = reactive(emptyForm())
 
 function emptyForm() {