feat: block manual issue-lock seeding and require lock disclosure (#447)

Add lock_provenance metadata on gitea_lock_issue writes and fail closed at
gitea_create_pr when provenance is missing. Final-report validation now
requires explicit External-state mutations disclosure for issue-lock
read/write/delete and blocks mixed author PR creation with reviewer approval.

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

gitea_mcp_server.py

@@ -538,6 +538,7 @@ import task_capability_map  # noqa: E402
 import review_proofs  # noqa: E402
 import agent_temp_artifacts
 import issue_lock_worktree  # noqa: E402
+import issue_lock_provenance  # noqa: E402
 import already_landed_reconcile  # noqa: E402
 import author_mutation_worktree  # noqa: E402
 import issue_claim_heartbeat  # noqa: E402
@@ -1208,6 +1209,10 @@ def gitea_lock_issue(
         "repo": r,
         "worktree_path": resolved_worktree,
         "work_lease": work_lease,
+        "lock_provenance": issue_lock_provenance.build_sanctioned_lock_provenance(
+            tool="gitea_lock_issue",
+            claimant=work_lease.get("claimant"),
+        ),
     }
 
     try:
@@ -1298,6 +1303,14 @@ def gitea_create_pr(
     except Exception as e:
         raise RuntimeError(f"Could not read issue lock file: {e} (fail closed)")
 
+    lock_provenance_check = issue_lock_provenance.assess_lock_file_for_create_pr(
+        lock_data
+    )
+    if lock_provenance_check["block"]:
+        raise RuntimeError(
+            issue_lock_provenance.format_lock_provenance_error(lock_provenance_check)
+        )
+
     locked_issue = lock_data.get("issue_number")
     locked_branch = lock_data.get("branch_name")
     locked_worktree = lock_data.get("worktree_path")