feat(review): review queue for leads + manual reviewer reassignment

Leads get the same two-queue view operators already have: 'Available
to Review' (pending reviews currently assigned to a peer lead) and
'My Assigned Reviews' (assigned to me), replacing the old single
'My Reviews' toggle. Since the load-balanced auto-assignment always
picks a reviewer immediately, 'available' means peer-assigned reviews
a lead could pick up if the assignee can't get to them, not unclaimed
ones (there aren't any).

POST /tests/{id}/assign now also accepts red_reviewer_assignee /
blue_reviewer_assignee, validated against the matching lead role and
synced to Jira the same way operator assignment already is. The
AssigneeControl UI gained a 'reviewer' kind (leads-only picker) shown
on the test detail header while a test sits in red_review/blue_review
— this also fixes the reviewer assignment being invisible in Aegis
even though it was already being pushed to Jira correctly.

frontend/src/api/tests.ts

@@ -179,10 +179,15 @@ export async function updateTestClassification(
   return data;
 }
 
-/** Assign red_tech/blue_tech operators to a test (leads + managers only). */
+/** Assign operators or hand off a review to a peer lead (leads + managers only). */
 export async function assignTestOperators(
   testId: string,
-  payload: { red_tech_assignee?: string | null; blue_tech_assignee?: string | null },
+  payload: {
+    red_tech_assignee?: string | null;
+    blue_tech_assignee?: string | null;
+    red_reviewer_assignee?: string | null;
+    blue_reviewer_assignee?: string | null;
+  },
 ): Promise<Test> {
   const { data } = await client.post<Test>(`/tests/${testId}/assign`, payload);
   return data;