docs: revise commerce modules overview pages (#10738)

* revise API Key Module overview

* revise auth module

* support ref sidebar items

* remove examples

* revise cart module

* revise currency

* revise customer module

* revise fulfillment module

* revise inventory module

* revise order module

* revise payment

* revise pricing module

* revise product module

* revise promotion module

* revise region module

* revise sales channel module

* revise stock location module

* revise store module

* revise tax module

* revise user module

* lint content + fix snippets

www/apps/resources/app/storefront-development/publishable-api-keys/page.mdx

@@ -3,6 +3,7 @@ tags:
   - publishable api key
   - api key
   - storefront
+  - sales channel
 ---
 
 export const metadata = {