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/components/test-detail/TestDetailHeader.tsx

@@ -93,7 +93,10 @@ interface TestDetailHeaderProps {
   onUpdateClassification: (value: DataClassification) => void;
   isUpdatingClassification: boolean;
   operators: OperatorOut[];
-  onAssignOperator: (side: "red" | "blue", userId: string | null) => void;
+  onAssignOperator: (
+    field: "red_tech_assignee" | "blue_tech_assignee" | "red_reviewer_assignee" | "blue_reviewer_assignee",
+    userId: string | null,
+  ) => void;
   isAssigningOperator: boolean;
 }
 
@@ -551,13 +554,37 @@ export default function TestDetailHeader({
 
         <div className="flex flex-col items-end gap-2">
           <div className="flex items-center gap-2">
+            {test.state === "red_review" && (
+              <AssigneeControl
+                side="red"
+                kind="reviewer"
+                assigneeId={test.red_reviewer_assignee}
+                operators={operators}
+                canEdit={role === "red_lead" || role === "manager"}
+                isSaving={isAssigningOperator}
+                onAssign={(userId) => onAssignOperator("red_reviewer_assignee", userId)}
+                size="lg"
+              />
+            )}
+            {test.state === "blue_review" && (
+              <AssigneeControl
+                side="blue"
+                kind="reviewer"
+                assigneeId={test.blue_reviewer_assignee}
+                operators={operators}
+                canEdit={role === "blue_lead" || role === "manager"}
+                isSaving={isAssigningOperator}
+                onAssign={(userId) => onAssignOperator("blue_reviewer_assignee", userId)}
+                size="lg"
+              />
+            )}
             <AssigneeControl
               side="red"
               assigneeId={test.red_tech_assignee}
               operators={operators}
               canEdit={role === "red_lead" || role === "manager"}
               isSaving={isAssigningOperator}
-              onAssign={(userId) => onAssignOperator("red", userId)}
+              onAssign={(userId) => onAssignOperator("red_tech_assignee", userId)}
               size="lg"
             />
             <AssigneeControl
@@ -566,7 +593,7 @@ export default function TestDetailHeader({
               operators={operators}
               canEdit={role === "blue_lead" || role === "manager"}
               isSaving={isAssigningOperator}
-              onAssign={(userId) => onAssignOperator("blue", userId)}
+              onAssign={(userId) => onAssignOperator("blue_tech_assignee", userId)}
               size="lg"
             />
           </div>