fix(jira): campaign=Task, campaign tests=Sub-task, standalone tests=Task

Root cause: Jira rejects Task-under-Task nesting ("Please select valid
parent issue"). Campaign tickets and test tickets were both created as
Task, so nesting test under campaign failed for all 62 APT32 tests.

Fix:
- JIRA_ISSUE_TYPE_CAMPAIGN: "Epic" -> "Task" (was unused, now used)
- JIRA_ISSUE_TYPE_SUBTASK: "Sub-task" (new config key)
- auto_create_campaign_issue: uses JIRA_ISSUE_TYPE_CAMPAIGN (Task)
- auto_create_test_issue: uses Sub-task when parent_ticket_override is
  set (campaign context), Task otherwise (standalone)

Hierarchy: OFS-9107 -> Campaign (Task) -> Test (Sub-task)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/config.py

@@ -52,7 +52,8 @@ class Settings(BaseSettings):
     JIRA_IS_CLOUD: bool = True
     JIRA_DEFAULT_PROJECT: str = ""
     JIRA_ISSUE_TYPE_TEST: str = "Task"
-    JIRA_ISSUE_TYPE_CAMPAIGN: str = "Epic"
+    JIRA_ISSUE_TYPE_CAMPAIGN: str = "Task"
+    JIRA_ISSUE_TYPE_SUBTASK: str = "Sub-task"
 
     # ── Tempo Integration ─────────────────────────────────────────────
     TEMPO_ENABLED: bool = False

backend/app/services/jira_service.py

@@ -393,7 +393,7 @@ def auto_create_campaign_issue(
             "project": {"key": project_key},
             "summary": f"[Aegis Campaign] {campaign.name}",
             "description": _build_campaign_description(campaign),
-            "issuetype": {"name": settings.JIRA_ISSUE_TYPE_TEST},
+            "issuetype": {"name": settings.JIRA_ISSUE_TYPE_CAMPAIGN},
             "labels": ["aegis", "campaign"],
         }
 
@@ -467,11 +467,18 @@ def auto_create_test_issue(
     try:
         jira = get_user_jira_client(actor, db)
 
+        # Tests nested under a campaign are Sub-tasks; standalone tests are Tasks
+        issue_type = (
+            settings.JIRA_ISSUE_TYPE_SUBTASK
+            if parent_ticket_override
+            else settings.JIRA_ISSUE_TYPE_TEST
+        )
+
         fields: dict = {
             "project": {"key": project_key},
             "summary": f"[Aegis] {mitre_id} — {test.name}",
             "description": _build_test_description(test, technique),
-            "issuetype": {"name": settings.JIRA_ISSUE_TYPE_TEST},
+            "issuetype": {"name": issue_type},
             "labels": ["aegis", "security-test", mitre_id.replace(".", "-")],
         }