fix: preserve document hierarchy in vault during pull

New documents now placed in parent's subdirectory (coll/Parent/Child.md)
instead of flat in the collection dir. Parent paths registered immediately
so nested children resolve correctly within the same pull.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

outline_sync.py

@@ -434,13 +434,18 @@ class OutlineSync:
                 print(f"ok: {rel} updated")
                 updated += 1
             else:
-                # New document — determine path from collection/title
+                # New document — determine path from collection + parent hierarchy
                 safe_coll = sanitize_name(
                     next((c["name"] for c in collections if c["id"] == coll_id), coll_id)
                 )
                 coll_dir = self.vault_dir / safe_coll
-                coll_dir.mkdir(parents=True, exist_ok=True)
-                path = self._unique_path(coll_dir, sanitize_name(title))
+                if parent_id and parent_id in vault_ids:
+                    parent_path = vault_ids[parent_id]
+                    target_dir = parent_path.parent / parent_path.stem
+                else:
+                    target_dir = coll_dir
+                target_dir.mkdir(parents=True, exist_ok=True)
+                path = self._unique_path(target_dir, sanitize_name(title))
                 fm = {
                     "outline_id":            doc_id,
                     "outline_collection_id": coll_id,
@@ -449,6 +454,7 @@ class OutlineSync:
                 }
                 content = build_frontmatter(fm) + "\n" + full.get("text", "")
                 path.write_text(content, encoding="utf-8")
+                vault_ids[doc_id] = path  # register so child docs resolve parent correctly
                 rel = str(path.relative_to(self.vault_dir))
                 print(f"ok: {rel} created")
                 created += 1