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_llm_agent_sha.py

@@ -22,6 +22,7 @@ from unittest.mock import patch
 
 sys.path.insert(0, str(__import__("pathlib").Path(__file__).resolve().parent.parent))
 
+import mcp_server  # noqa: E402
 from mcp_server import (  # noqa: E402
     gitea_check_pr_eligibility,
     gitea_merge_pr,
@@ -130,6 +131,7 @@ class TestShaCannotBypassSelfReview(unittest.TestCase):
         ]
         from mcp_server import init_review_decision_lock, gitea_mark_final_review_decision
         init_review_decision_lock("prgs", "review_pr")
+        mcp_server.gitea_load_review_workflow()
         gitea_mark_final_review_decision(9, "approve", remote="prgs")
         env = self._env(SHA_WOULD_BE_REVIEWER, "reviewer")
         with patch.dict(os.environ, env, clear=True):