fix(mcp): allow create_issue from clean control checkout (#749)

Provide a narrow phase-scoped bootstrap so gitea_create_issue can run from
a clean canonical control checkout when no issue number—and therefore no
issue-backed worktree—can exist yet. Dirty roots, non-base branches, base
races, foreign workspaces, and all post-creation author mutations remain
fail-closed under the ordinary branches-only guard.

Closes #749.

workflow_scope_guard.py

@@ -278,12 +278,19 @@ def assess_root_source_mutation(
     current_branch: str | None = None,
     locked_issue_number: int | None = None,
     role_kind: str | None = None,
+    mutation_task: str | None = None,
 ) -> dict[str, Any]:
     """Fail closed for diagnostic/source edits on the control/root checkout.
 
     Allowed only when the active workspace is under ``branches/``. Dirty
     tracked source/test files on the control checkout always block, including
     temporary/diagnostic/test-only intent.
+
+    #749: ``create_issue`` is a pure remote mutation with no local tree write.
+    When *mutation_task* is create_issue and the control checkout has no dirty
+    source/test files, the missing-worktree signal is suppressed so the
+    sanctioned bootstrap path can proceed. Dirty roots and every other task
+    still fail closed.
     """
     role = (role_kind or "").strip().lower()
     if role == "reconciler":
@@ -302,6 +309,7 @@ def assess_root_source_mutation(
     dirty_src = dirty_source_files(porcelain_status)
     reasons: list[str] = []
     blocker_kind: str | None = None
+    create_issue_bootstrap = False
 
     if not under_branches and workspace == root and dirty_src:
         # Root workspace with source dirtiness is unattributed root WIP.
@@ -313,32 +321,50 @@ def assess_root_source_mutation(
         )
         blocker_kind = BLOCKER_ROOT_DIAGNOSTIC_EDIT
 
+    # Lazy import keeps workflow_scope_guard free of circular import at module load.
+    try:
+        import create_issue_bootstrap as _cib
+    except Exception:  # pragma: no cover - import always available in-tree
+        _cib = None
+
     if (
         not under_branches
         and workspace == root
         and not dirty_src
         and role == "author"
     ):
-        # Explicit missing-worktree signal for force-on author entrypoints.
-        reasons.append(
-            "author source/test mutation from the stable control checkout is "
-            "forbidden; bind an issue-backed worktree under branches/ first"
-        )
-        blocker_kind = BLOCKER_MISSING_WORKTREE
+        if _cib is not None and _cib.is_create_issue_task(mutation_task):
+            # #749: clean-root create_issue is the sanctioned bootstrap path.
+            create_issue_bootstrap = True
+        else:
+            # Explicit missing-worktree signal for force-on author entrypoints.
+            reasons.append(
+                "author source/test mutation from the stable control checkout is "
+                "forbidden; bind an issue-backed worktree under branches/ first"
+            )
+            blocker_kind = BLOCKER_MISSING_WORKTREE
 
     if reasons:
         kind = blocker_kind or BLOCKER_ROOT_DIAGNOSTIC_EDIT
+        next_action = _NEXT_ACTIONS[kind]
+        if (
+            kind == BLOCKER_ROOT_DIAGNOSTIC_EDIT
+            and _cib is not None
+            and _cib.is_create_issue_task(mutation_task)
+        ):
+            next_action = _cib.EXACT_NEXT_ACTION_BOOTSTRAP
         return {
             "proven": False,
             "block": True,
             "blocker_kind": kind,
-            "exact_next_action": _NEXT_ACTIONS[kind],
+            "exact_next_action": next_action,
             "reasons": reasons,
             "dirty_source_files": dirty_src,
             "workspace_path": workspace,
             "canonical_repo_root": root,
             "under_branches": under_branches,
             "locked_issue_number": locked_issue_number,
+            "create_issue_bootstrap": False,
         }
     return {
         "proven": True,
@@ -351,6 +377,7 @@ def assess_root_source_mutation(
         "canonical_repo_root": root,
         "under_branches": under_branches,
         "locked_issue_number": locked_issue_number,
+        "create_issue_bootstrap": create_issue_bootstrap,
     }
 
 
@@ -365,6 +392,7 @@ def assess_production_mutation_guards(
     role_kind: str | None = None,
     require_author_lock: bool = False,
     in_test_mode: bool = False,
+    mutation_task: str | None = None,
 ) -> dict[str, Any]:
     """Compose root + scope production guards when they must be active (#683)."""
     if not production_guards_active(in_test_mode=in_test_mode):
@@ -385,6 +413,7 @@ def assess_production_mutation_guards(
         current_branch=current_branch,
         locked_issue_number=locked_issue_number,
         role_kind=role_kind,
+        mutation_task=mutation_task,
     )
     if root_assess["block"]:
         return {**root_assess, "skipped": False}
@@ -408,6 +437,7 @@ def assess_production_mutation_guards(
         "skipped": False,
         "root": root_assess,
         "scope": scope_assess,
+        "create_issue_bootstrap": bool(root_assess.get("create_issue_bootstrap")),
     }