fix(campaigns,tests): admin cannot create campaigns, manager can delete unstarted tests, intensify red/blue team colors

- Campaign creation and generate-from-threat-actor now use the strict
  role check — admin no longer gets a free pass into campaign content,
  same principle already applied to test-template creation.
- New manager-only DELETE /tests/{id}: removes a standalone test still
  in draft (not started, not linked to any campaign).
- Replaced the orange/indigo stand-ins used across team badges, tabs,
  action buttons, and timers with true red/blue so Red Team and Blue
  Team read unambiguously at a glance.

backend/tests/test_admin_excluded_from_test_workflow.py

@@ -39,6 +39,8 @@ DUMMY_ID = str(uuid.uuid4())
         ("post", "/api/v1/tests", {"technique_id": DUMMY_ID, "name": "x"}),
         ("post", "/api/v1/tests/from-template", {"template_id": DUMMY_ID, "technique_id": DUMMY_ID}),
         ("post", "/api/v1/tests/import-rt", {"name": "x", "techniques": []}),
+        ("post", "/api/v1/campaigns", {"name": "x"}),
+        ("post", f"/api/v1/campaigns/from-threat-actor/{DUMMY_ID}", None),
     ],
 )
 def test_admin_forbidden(client, auth_headers, method, path, payload):