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/shared/api/types.ts

@@ -26,12 +26,9 @@ export type BaseRecord = {
 
 /**
  * PocketBase collection for simple text blocks (Intro, Bio).
+ * Each collection is named after its section — no slug field.
  */
 export type PageContentRecord = BaseRecord & {
-  /**
-   * Slug corresponding to the parent section
-   */
-  slug: string;
   /**
    * HTML or Markdown content string
    */