fix: Private tab in library now shows pages by parent_section, not workspace

Bug: lib_private filtered on p.source == '🔒 Private' which only matched pages
without a workspace. All pages have parent_section='Private' by default, so
filtering by source excluded them all.

Fix: add 'section' field to page dict from parent_section DB column,
filter lib_private by p.section == 'Private'

app/routers/dashboard.py

@@ -105,6 +105,7 @@ async def library_page(request: Request, owner: str = Query(default=""), repo: s
             "source": r.get("workspace") or "🔒 Private",
             "last_edited": r.get("updated_at", "now"),
             "last_visited": r.get("updated_at", "now"),
+            "section": r.get("parent_section", "Private"),
         }
 
     all_pages = [to_page(r) for r in rows]
@@ -136,7 +137,7 @@ async def library_page(request: Request, owner: str = Query(default=""), repo: s
     sidebar["lib_recent"] = all_pages
     sidebar["lib_favorites"] = lib_favs
     sidebar["lib_shared"] = []
-    sidebar["lib_private"] = [p for p in all_pages if p.get("source") == "🔒 Private"]
+    sidebar["lib_private"] = [p for p in all_pages if p.get("section") == "Private"]
     sidebar["lib_has_favorites"] = len(lib_favs) > 0
     sidebar["lib_has_shared"] = False