fix(#4256): resolve todos from the root via todosDir everywhere (#4479)

* test(#4256): pin todos as root-scoped under workstreams (RED)

* fix(#4256): resolve todos from the root via todosDir everywhere

* chore(#4256): changeset fragment (pr number to backfill)

* chore(#4256): backfill PR number in changeset

---------

Co-authored-by: sim <sim@local>

src/planning-workspace.cts

@@ -304,6 +304,7 @@ interface PlanningPaths {
   requirements: string;
   debug: string;
   quick: string;
+  todos: string;
 }
 
 // #2142: the quick-task directory. Exported as its own function (not only as a
@@ -316,6 +317,33 @@ function quickDirFrom(planningBase: string): string {
   return path.join(planningBase, 'quick');
 }
 
+// #4256: the todos directory — deliberately ROOT-SCOPED, unlike every other
+// planningPaths key. Todos are shared project state by construction: the
+// migrateToWorkstreams contract keeps them among the shared files that "stay
+// in place" at .planning/todos/ (workstream.cts), and every workflow writer
+// writes that literal cwd-relative root path. The six todos readers
+// previously hand-composed `path.join(planningDir(cwd), 'todos', ...)`,
+// which silently re-scoped to .planning/workstreams/<ws>/todos/ — a
+// directory nothing creates — under a workstream, so todos went invisible
+// and audit-open passed the milestone-close gate vacuously. Same
+// two-composers-of-one-path shape the `debug` (#3149) and `quick` (#2142)
+// keys were introduced to eliminate (DEFECT.GENERATIVE-FIX).
+//
+// Exported as its own function pair (not only as a `planningPaths` key)
+// because `audit.cts`'s `scanTodos`/`cmdAuditAcknowledge` consume an
+// already-resolved todos base rather than a `cwd`, mirroring how #2142
+// exported `quickDirFrom` for `scanQuickTasks`. `todosDir` takes NO ws/project
+// parameter — todos have no workstream- or project-scoped form anywhere, so
+// there is no discriminator to thread. This is also the single root #4327's
+// future filename-containment guard should enforce against.
+function todosDirFrom(planningBase: string): string {
+  return path.join(planningBase, 'todos');
+}
+
+function todosDir(cwd: string): string {
+  return todosDirFrom(planningRoot(cwd));
+}
+
 function planningPaths(cwd: string, ws?: string | null): PlanningPaths {
   const base = planningDir(cwd, ws);
   return {
@@ -332,6 +360,11 @@ function planningPaths(cwd: string, ws?: string | null): PlanningPaths {
     debug: path.join(base, 'debug'),
     // #2142: quick-task directory, composed via the shared quickDirFrom helper.
     quick: quickDirFrom(base),
+    // #4256: todos directory — deliberately ROOT-scoped while the rest of
+    // this record follows the active workstream/project (todos are shared
+    // project state per the migrateToWorkstreams contract), composed via the
+    // shared todosDir helper so this key and every direct caller agree.
+    todos: todosDir(cwd),
   };
 }
 
@@ -638,6 +671,8 @@ export = {
   listAvailableWorkstreams,
   planningPaths,
   quickDirFrom,
+  todosDirFrom,
+  todosDir,
   withPlanningLock,
   getActiveWorkstream,
   peekActiveWorkstream,