feat(core): add title order by (#12696)

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **New Features**
  - Added support for ordering documents by their title.
  - Introduced a new "title" system property type with an associated icon and display name.

- **Improvements**
  - Enhanced system property types to allow more flexible filtering options.
  - Improved filter condition handling to show an unknown filter UI when filtering methods or values are unavailable.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/core/src/modules/doc/services/docs.ts

@@ -81,6 +81,10 @@ export class DocsService extends Service {
     return this.store.watchTrashDocIds();
   }
 
+  allDocTitle$() {
+    return this.store.watchAllDocTitle();
+  }
+
   constructor(
     private readonly store: DocsStore,
     private readonly docPropertiesStore: DocPropertiesStore,

packages/frontend/core/src/modules/doc/stores/docs.ts

@@ -142,6 +142,25 @@ export class DocsStore extends Store {
     );
   }
 
+  watchAllDocTitle() {
+    return yjsGetPath(
+      this.workspaceService.workspace.rootYDoc.getMap('meta'),
+      'pages'
+    ).pipe(
+      switchMap(pages => yjsObservePath(pages, '*.title')),
+      map(pages => {
+        if (pages instanceof YArray) {
+          return pages.map(v => ({
+            id: v.get('id') as string,
+            title: (v.get('title') ?? '') as string,
+          }));
+        } else {
+          return [];
+        }
+      })
+    );
+  }
+
   watchNonTrashDocIds() {
     return yjsGetPath(
       this.workspaceService.workspace.rootYDoc.getMap('meta'),