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.

frontend/src/api/tests.ts

@@ -372,6 +372,11 @@ export async function resumeTest(testId: string): Promise<Test> {
   return data;
 }
 
+/** Delete a standalone test that hasn't started yet. Manager only. */
+export async function deleteTest(testId: string): Promise<void> {
+  await client.delete(`/tests/${testId}`);
+}
+
 // ── Timeline ───────────────────────────────────────────────────────
 
 /** Get the audit-log timeline for a test. */