feat: classify merge simulation as worktree/index mutations (Closes #317)

Add assess_merge_simulation_report to reject local merge simulations listed
as read-only diagnostics and require Worktree/index mutations documentation
with worktree path, pre/merge/abort/post-clean proof when simulation
commands appear in the session log.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

tests/test_llm_workflow_split.py

@@ -121,4 +121,10 @@ def test_start_issue_template_references_work_issue_workflow():
 def test_create_issue_final_report_verifier_exported():
     from review_proofs import assess_create_issue_final_report
 
-    assert callable(assess_create_issue_final_report)
+    assert callable(assess_create_issue_final_report)
+
+
+def test_merge_simulation_verifier_exported():
+    from review_proofs import assess_merge_simulation_report
+
+    assert callable(assess_merge_simulation_report)

tests/test_reviewer_merge_simulation.py

@@ -0,0 +1,135 @@
+"""Tests for merge-simulation worktree mutation verifier (#317)."""
+import sys
+import unittest
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+from reviewer_merge_simulation import (  # noqa: E402
+    assess_merge_simulation_report,
+    merge_simulation_commands,
+)
+
+
+def _good_simulation_report(**overrides) -> str:
+    lines = [
+        "Worktree/index mutations: merge simulation in branches/review-pr281",
+        "Worktree path: branches/review-pr281",
+        "Pre-simulation clean status: clean (git status --porcelain empty)",
+        "Merge result: conflicts in review_proofs.py",
+        "Abort command: git merge --abort",
+        "Post-abort clean status: clean after abort (git status --porcelain empty)",
+    ]
+    text = "\n".join(lines)
+    for key, value in overrides.items():
+        text = text.replace(f"{key}:", f"{key}: {value}")
+    return text
+
+
+class TestMergeSimulationDetection(unittest.TestCase):
+    def test_detects_no_commit_merge(self):
+        commands = merge_simulation_commands([
+            "git merge prgs/master --no-commit --no-ff",
+            "git status",
+        ])
+        self.assertEqual(commands, ["git merge prgs/master --no-commit --no-ff"])
+
+    def test_detects_merge_abort(self):
+        commands = merge_simulation_commands([
+            "git merge prgs/master --no-commit --no-ff",
+            "git merge --abort",
+        ])
+        self.assertIn("git merge --abort", commands)
+
+
+class TestMergeSimulationReport(unittest.TestCase):
+    def test_no_simulation_passes(self):
+        result = assess_merge_simulation_report(
+            "Review complete. Worktree/index mutations: none",
+            command_log=["git status --porcelain", "git diff prgs/master...HEAD"],
+        )
+        self.assertTrue(result["proven"])
+
+    def test_documented_simulation_passes(self):
+        report = _good_simulation_report()
+        result = assess_merge_simulation_report(
+            report,
+            command_log=[
+                "git merge prgs/master --no-commit --no-ff",
+                "git merge --abort",
+            ],
+        )
+        self.assertTrue(result["proven"], result["reasons"])
+
+    def test_readonly_classification_blocks(self):
+        report = "\n".join([
+            "Read-only diagnostics: git merge prgs/master --no-commit --no-ff, git status",
+            "Worktree/index mutations: none",
+        ])
+        result = assess_merge_simulation_report(
+            report,
+            command_log=["git merge prgs/master --no-commit --no-ff"],
+        )
+        self.assertFalse(result["proven"])
+        self.assertTrue(result["block"])
+        self.assertTrue(any("read-only" in r.lower() for r in result["reasons"]))
+
+    def test_missing_worktree_field_blocks(self):
+        report = "Merge simulation ran but only noted in prose."
+        result = assess_merge_simulation_report(
+            report,
+            command_log=["git merge prgs/master --no-commit --no-ff"],
+        )
+        self.assertFalse(result["proven"])
+        self.assertTrue(any("worktree/index mutations" in r.lower() for r in result["reasons"]))
+
+    def test_conflict_simulation_requires_merge_result(self):
+        report = _good_simulation_report().replace(
+            "Merge result: conflicts in review_proofs.py",
+            "",
+        )
+        result = assess_merge_simulation_report(
+            report,
+            command_log=["git merge prgs/master --no-commit --no-ff"],
+        )
+        self.assertFalse(result["proven"])
+        self.assertTrue(any("merge result" in r.lower() for r in result["reasons"]))
+
+    def test_aborted_simulation_requires_post_clean_proof(self):
+        report = _good_simulation_report().replace(
+            "Post-abort clean status: clean after abort (git status --porcelain empty)",
+            "",
+        )
+        result = assess_merge_simulation_report(
+            report,
+            command_log=[
+                "git merge prgs/master --no-commit --no-ff",
+                "git merge --abort",
+            ],
+        )
+        self.assertFalse(result["proven"])
+        self.assertTrue(any("post-abort" in r.lower() for r in result["reasons"]))
+
+    def test_successful_simulation_without_abort_omits_abort_fields(self):
+        report = "\n".join([
+            "Worktree/index mutations: merge simulation completed cleanly",
+            "Worktree path: branches/review-pr281",
+            "Pre-simulation clean status: clean before simulation",
+            "Merge result: clean fast-forward simulation",
+        ])
+        result = assess_merge_simulation_report(
+            report,
+            command_log=["git merge prgs/master --no-commit --no-ff"],
+        )
+        self.assertTrue(result["proven"], result["reasons"])
+
+
+class TestExport(unittest.TestCase):
+    def test_review_proofs_reexport(self):
+        from review_proofs import assess_merge_simulation_report as exported
+
+        self.assertTrue(callable(exported))
+
+
+if __name__ == "__main__":
+    unittest.main()