feat(permissions): admin no longer acts on the test workflow; managers coordinate operators

Admin administers the site — it no longer has any override on
validate-red/blue, review-red/blue, resolve-dispute, request-discussion,
reopen, hold, resume, assign-operators, or classification-update.
Introduces require_any_role_strict(), a role dependency without the
global admin bypass, so these specific endpoints truly exclude admin
instead of only removing it from the (redundant) role tuple.

Managers gain the ability to assign red_tech/blue_tech operators
(POST /tests/{id}/assign, GET /users/operators) alongside leads, since
that's coordination, not resolving a ticket.

Also enlarges and repositions the operator-assignment controls next
to the Start Execution button, and fixes a literal '\u2014' rendering
as text instead of an em dash in the test detail technique line.

backend/app/services/test_workflow_service.py

@@ -1228,13 +1228,12 @@ def resolve_dispute(db: Session, test: Test, user: User, target_team: str, notes
     if target_team not in ("red", "blue"):
         raise InvalidOperationError("target_team must be 'red' or 'blue'")
 
-    if user.role != "admin":
-        is_red_approver = user.role == "red_lead" and test.red_validation_status == "approved"
-        is_blue_approver = user.role == "blue_lead" and test.blue_validation_status == "approved"
-        if not (is_red_approver or is_blue_approver):
-            raise InvalidOperationError(
-                "Only the lead who approved can flip their vote to resolve this dispute"
-            )
+    is_red_approver = user.role == "red_lead" and test.red_validation_status == "approved"
+    is_blue_approver = user.role == "blue_lead" and test.blue_validation_status == "approved"
+    if not (is_red_approver or is_blue_approver):
+        raise InvalidOperationError(
+            "Only the lead who approved can flip their vote to resolve this dispute"
+        )
 
     entity = TestEntity.from_orm(test)
     entity.resolve_dispute_reject(target_team)