fix: update COPILOT_AGENT_ASSIGNEE from 'copilot+gpt-5.3-codex' to 'copilot'

Co-authored-by: Steake <530040+Steake@users.noreply.github.com>

Author: Copilot

repo_architect.py

@@ -198,7 +198,7 @@
 # Labels required for an issue to be eligible for execution selection
 EXECUTION_ELIGIBLE_LABELS: Tuple[str, ...] = ("arch-gap", "copilot-task", "needs-implementation")
 # GitHub Copilot coding agent assignee username
-COPILOT_AGENT_ASSIGNEE = "copilot+gpt-5.3-codex"
+COPILOT_AGENT_ASSIGNEE = "copilot"
 # Canonical architectural objectives aligned with charter §14 priority order
 OBJECTIVE_LABELS: Dict[str, str] = {
     "restore-parse-correctness": "Restore or preserve parse correctness (Lane 2)",

tests/test_repo_architect.py

@@ -3515,7 +3515,7 @@ def test_merged_lifecycle_added_on_merged_pr(self) -> None:
         self.assertNotIn("pr-open", new_labels)
 
     def test_copilot_assignee_constant(self) -> None:
-        self.assertEqual(ra.COPILOT_AGENT_ASSIGNEE, "copilot+gpt-5.3-codex")
+        self.assertEqual(ra.COPILOT_AGENT_ASSIGNEE, "copilot")
 
 
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