fix: align PocketBase type definitions with actual schema

Remove slug field from PageContentRecord (intro/bio collections have none).
Remove number field from SectionRecord (not stored in PocketBase); derive
zero-padded display number from the order field at render time.

src/entities/Section/model/types.ts

@@ -12,10 +12,6 @@ export type SectionRecord = BaseRecord & {
    * Display name of the section
    */
   title: string;
-  /**
-   * Visual numbering prefix (e.g., "01")
-   */
-  number: string;
   /**
    * Sorting weight for section order
    */