feat: gate reviewer mutations on canonical workflow load proof (Closes #389)

Add gitea_load_review_workflow and in-process session proof required before
gitea_submit_pr_review, gitea_mark_final_review_decision, and gitea_merge_pr.
Capability and runtime context report workflow-load status; stale or missing
proof fails closed with recovery handoff text that forbids approve/merge replay.

tests/test_permission_reports.py

@@ -230,6 +230,7 @@ class TestEligibilityDenialReport(PermissionReportBase):
             return PR_PAYLOAD
         mock_api.side_effect = fake_api
         mcp_server.init_review_decision_lock("prgs", "review_pr")
+        mcp_server.gitea_load_review_workflow()
         mcp_server.gitea_mark_final_review_decision(42, "approve", remote="prgs")
         with patch.dict(os.environ, self._env("author-profile")):
             res = mcp_server.gitea_submit_pr_review(
@@ -272,6 +273,7 @@ class TestReviewCommentPathUsesCanonicalOp(PermissionReportBase):
             return PR_PAYLOAD
         mock_api.side_effect = fake_api
         mcp_server.init_review_decision_lock("prgs", "review_pr")
+        mcp_server.gitea_load_review_workflow()
         mcp_server.gitea_mark_final_review_decision(42, "comment", remote="prgs")
         with patch.dict(os.environ, self._env("author-profile")):
             res = mcp_server.gitea_submit_pr_review(