feat(templates,campaigns): validate MITRE technique IDs, surface template suggestions first, manager can re-approve rejected campaigns

- TestTemplate/TemplateSuggestion creation and updates now reject any
  mitre_technique_id that doesn't match a real, already-synced MITRE
  ATT&CK technique. Frontend swaps the free-text ID input for a
  technique picker.
- Test Catalog now shows pending template suggestions before the
  catalog grid, with full field detail (platform, severity, tool,
  atomic ID, source URL, remediation) instead of just name/procedure.
- A manager can edit and directly re-approve a campaign they previously
  rejected, instead of needing the original lead to resubmit it.

backend/app/routers/campaigns.py

@@ -431,15 +431,19 @@ def update_campaign(
     # Entry: db
     db: Session = Depends(get_db),
     # Entry: current_user
-    current_user: User = Depends(require_any_role("red_lead", "blue_lead")),
+    current_user: User = Depends(require_any_role("red_lead", "blue_lead", "manager")),
 ) -> dict:
     """Update a campaign. Only allowed in draft or active state.
 
+    A manager may only edit a campaign that's sitting in draft with a
+    rejection_reason set (i.e. one they previously rejected) — see
+    ``update_campaign()``'s ownership check.
+
     Args:
         campaign_id (str): UUID string of the campaign to update.
         payload (CampaignUpdate): Partial update payload; only set fields are applied.
         db (Session): SQLAlchemy database session.
-        current_user (User): Authenticated red_lead or blue_lead performing the update.
+        current_user (User): Authenticated red_lead, blue_lead, or manager performing the update.
 
     Returns:
         dict: Serialised representation of the updated campaign.