fix: resolve conflicts for PR #374

Merge prgs/master into feat/issue-274-branches-only-worktrees; keep both
already_landed_reconcile and author_mutation_worktree imports. Allow
branches/ worktrees when PROJECT_ROOT is the session worktree; align
commit-payload tests with branches-only guard (#274).

author_mutation_worktree.py

@@ -62,18 +62,20 @@ def assess_author_mutation_worktree(
     workspace = os.path.realpath(workspace_path)
     branch = (current_branch or "").strip()
 
-    if workspace == root:
-        reasons.append(
-            "author mutation blocked: workspace is the stable control checkout; "
-            "create or switch to a session-owned worktree under branches/"
-        )
-    elif not is_path_under_branches(workspace, root):
-        reasons.append(
-            f"author mutation blocked: workspace '{workspace}' is not under "
-            f"'{root}/branches/'; create a branches/<task> worktree first"
-        )
+    under_branches = is_path_under_branches(workspace, root)
+    if not under_branches:
+        if workspace == root:
+            reasons.append(
+                "author mutation blocked: workspace is the stable control checkout; "
+                "create or switch to a session-owned worktree under branches/"
+            )
+        else:
+            reasons.append(
+                f"author mutation blocked: workspace '{workspace}' is not under "
+                f"'{root}/branches/'; create a branches/<task> worktree first"
+            )
 
-    if workspace == root and branch and branch not in bases:
+    if not under_branches and workspace == root and branch and branch not in bases:
         reasons.append(
             f"control checkout drift: branch '{branch}' is not a stable base "
             f"branch ({'/'.join(sorted(bases))})"