fix: use {{cpt_slug}} instead of {{slug}} for post type identifiers

Corrected post type slug references to use the specific {{cpt_slug}} mustache
variable instead of the generic {{slug}} (plugin slug) variable.

According to generate-plugin.instructions.md, {{cpt_slug}} is the dedicated
variable for custom post type slugs (max 20 chars), while {{slug}} is the
plugin identifier.

Changed:
- inc/class-post-types.php: POST_TYPE constant
- src/hooks/usePostType.js: Default postType parameter
- src/hooks/useFields.js: Default postType parameter
- src/hooks/useRepeater.js: Default postType parameter
- src/hooks/useCollection.js: Default postType parameter
- src/components/PostSelector: Default postType parameter
- docs/GENERATE-PLUGIN.md: Documentation example

This ensures proper separation between plugin slug and CPT slug during
scaffold generation.

Author: ashleyshaw

docs/GENERATE-PLUGIN.md

@@ -218,7 +218,7 @@ Block registration and components use namespace and textdomain:
 /**
  * @package {{namespace}}
  */
-export default function PostSelector( { postType = '{{slug}}' } ) {
+export default function PostSelector( { postType = '{{cpt_slug}}' } ) {
     return (
         <div className="{{namespace}}-post-selector">
             {__( 'Select Post', '{{textdomain}}' )}

inc/class-post-types.php

@@ -23,7 +23,7 @@ class Post_Types {
 	 *
 	 * @var string
 	 */
-	const POST_TYPE = '{{slug}}';
+	const POST_TYPE = '{{cpt_slug}}';
 
 	/**
 	 * Constructor.

src/components/PostSelector/PostSelector.js

@@ -24,7 +24,7 @@ import { ComboboxControl, Spinner } from '@wordpress/components';
  * @return {Element} PostSelector component.
  */
 export default function PostSelector({
-	postType = '{{slug}}',
+	postType = '{{cpt_slug}}',
 	value,
 	onChange,
 	label = __('Select Post', '{{textdomain}}'),

src/hooks/useCollection.js

@@ -17,7 +17,7 @@ import { useSelect } from '@wordpress/data';
  */
 export default function useCollection(query = {}) {
 	const {
-		postType = '{{slug}}',
+		postType = '{{cpt_slug}}',
 		perPage = 6,
 		page = 1,
 		order = 'desc',

src/hooks/useFields.js

@@ -16,7 +16,7 @@ import { useSelect } from '@wordpress/data';
  *
  * @return {Object} Fields data and loading state.
  */
-export default function useFields(postId, postType = '{{slug}}') {
+export default function useFields(postId, postType = '{{cpt_slug}}') {
 	return useSelect(
 		(select) => {
 			if (!postId) {

src/hooks/usePostType.js

@@ -16,7 +16,7 @@ import { useSelect } from '@wordpress/data';
  *
  * @return {Object} Post data and loading state.
  */
-export default function usePostType(postId, postType = '{{slug}}') {
+export default function usePostType(postId, postType = '{{cpt_slug}}') {
 	return useSelect(
 		(select) => {
 			if (!postId) {

src/hooks/useRepeater.js

@@ -20,7 +20,7 @@ import { useSelect } from '@wordpress/data';
 export default function useRepeater(
 	postId,
 	fieldName,
-	postType = '{{slug}}'
+	postType = '{{cpt_slug}}'
 ) {
 	return useSelect(
 		(select) => {