fix: anti-stomp capability auth, inventory wiring, side-effect proof (#604)

Address REQUEST_CHANGES on PR #680:

Blocker A — role vs capability agreement
- authorization_compatible allows reviewer/merger when they hold the task's
  required permission (e.g. gitea.issue.comment on comment_issue/mark_issue/
  set_issue_labels/lock_issue) without broad role-bypass.
- Unauthorized escalation without the permission remains fail closed.
- Regression coverage for allowed and denied reviewer/merger cases.

Blocker B — MUTATION_TASKS matches runtime wiring
- Remove unenforced entries; document dedicated-gate exclusions
  (mark_final_review_decision, save/resume_review_draft, etc.).
- Wire non-closing gitea_edit_pr as edit_pr; acquire lease uses
  acquire_reviewer_pr_lease task through verify_preflight_purity.
- Inventory↔wiring consistency tests replace set-membership-only coverage.

Blocker C — entrypoint side-effect ordering
- Behavioral tests for merge_pr, submit_pr_review, and comment_issue prove
  the assessor block aborts before Gitea API mutation and local durable writes.

Validation: 43 focused anti-stomp + related suites green; full suite
2639 passed / 6 skipped.

Closes #604

gitea_mcp_server.py

@@ -671,12 +671,18 @@ def _run_anti_stomp_preflight(
     profile = get_profile()
     profile_name = profile.get("profile_name")
     profile_role = _actual_profile_role()
+    allowed_operations = list(profile.get("allowed_operations") or [])
     req_role = None
+    req_perm = None
     if task:
         try:
             req_role = task_capability_map.required_role(task)
         except KeyError:
             req_role = _preflight_resolved_role
+        try:
+            req_perm = task_capability_map.required_permission(task)
+        except KeyError:
+            req_perm = None
 
     ctx = _resolve_namespace_mutation_context(worktree_path)
     workspace = ctx["workspace_path"]
@@ -734,7 +740,6 @@ def _run_anti_stomp_preflight(
         "approve_pr",
         "request_changes_pr",
         "merge_pr",
-        "mark_final_review_decision",
     }:
         try:
             wf_reasons = _review_workflow_load_gate_reasons()
@@ -765,6 +770,8 @@ def _run_anti_stomp_preflight(
         profile_name=profile_name,
         profile_role=profile_role,
         required_role=req_role or _preflight_resolved_role,
+        required_permission=req_perm,
+        allowed_operations=allowed_operations,
         workspace_path=workspace,
         project_root=canonical_root,
         current_branch=git_state.get("current_branch"),
@@ -5030,7 +5037,12 @@ def gitea_edit_pr(
         raise ValueError("At least one field to edit (title, body, state, base) must be provided.")
 
     closing = payload.get("state") == "closed"
-    verify_preflight_purity(remote, task="close_pr" if closing else None)
+    # Closing uses close_pr; non-closing title/body/base edits use edit_pr so
+    # the shared #604 anti-stomp inventory stays consistent with wiring.
+    if closing:
+        verify_preflight_purity(remote, task="close_pr")
+    else:
+        verify_preflight_purity(remote, task="edit_pr")
 
     # PR closure is a first-class capability, distinct from retitling or
     # rebasing edits (#216). Gate BEFORE auth/API setup so a blocked close
@@ -7650,7 +7662,11 @@ def gitea_acquire_reviewer_pr_lease(
             "permission_report": _permission_block_report("gitea.pr.comment"),
         }
 
-    _verify_role_mutation_workspace(remote, worktree=worktree, task="review_pr")
+    # task=acquire_reviewer_pr_lease so verify_preflight_purity runs shared #604
+    # anti-stomp for the declared lease-acquire mutation inventory entry.
+    _verify_role_mutation_workspace(
+        remote, worktree=worktree, task="acquire_reviewer_pr_lease"
+    )
     h, o, r = _resolve(remote, host, org, repo)
     auth = _auth(h)
     profile = get_profile()
@@ -7791,6 +7807,7 @@ def gitea_adopt_merger_pr_lease(
             "permission_report": _permission_block_report("gitea.pr.merge"),
         }
 
+    # task=adopt_merger_pr_lease so verify_preflight_purity runs shared #604 anti-stomp.
     _verify_role_mutation_workspace(
         remote, worktree=worktree, task="adopt_merger_pr_lease"
     )