docs: update stale auth hook links (#46948)

This updates the remaining stale auth hook references after the auth
hooks guide moved from hash anchors to dedicated subpages.

It switches the RBAC guide to the current custom access token hook page,
updates the MFA verification hook reference in both the docs error-code
source and the shared-data export, and fixes the matching custom access
token hook comments in the Slack Clone SQL examples.

Testing: not run. Link-target updates only.

Refs #46947


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

## Summary by CodeRabbit

## Release Notes

* **Documentation**
* Updated error code and auth hook documentation reference links to
point to more specific canonical documentation pages, improving accuracy
of references for developers.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

apps/docs/content/errorCodes/authErrorCodes.toml

@@ -126,7 +126,7 @@ description = "MFA challenge could not be verified -- wrong TOTP code."
 [mfa_verification_rejected]
 description = "Further MFA verification is rejected. Only returned if the MFA verification attempt hook returns a reject decision."
 [[mfa_verification_rejected.references]]
-href = "https://supabase.com/docs/guides/auth/auth-hooks?language=add-admin-role#hook-mfa-verification-attempt"
+href = "https://supabase.com/docs/guides/auth/auth-hooks/mfa-verification-hook"
 description = "MFA verification hook"
 
 [mfa_verified_factor_exists]

apps/docs/content/guides/api/custom-claims-and-role-based-access-control-rbac.mdx

@@ -18,7 +18,7 @@ Custom Claims are special attributes attached to a user that you can use to cont
 }
 ```
 
-To implement Role-Based Access Control (RBAC) with `custom claims`, use a [Custom Access Token Auth Hook](/docs/guides/auth/auth-hooks#hook-custom-access-token). This hook runs before a token is issued. You can use it to add additional claims to the user's JWT.
+To implement Role-Based Access Control (RBAC) with `custom claims`, use a [Custom Access Token Auth Hook](/docs/guides/auth/auth-hooks/custom-access-token-hook). This hook runs before a token is issued. You can use it to add additional claims to the user's JWT.
 
 This guide uses the [Slack Clone example](https://github.com/supabase/supabase/tree/master/examples/slack-clone/nextjs-slack-clone) to demonstrate how to add a `user_role` claim and use it in your [Row Level Security (RLS) policies](/docs/guides/database/postgres/row-level-security).
 
@@ -71,7 +71,7 @@ values
 
 ## Create Auth Hook to apply user role
 
-The [Custom Access Token Auth Hook](/docs/guides/auth/auth-hooks#hook-custom-access-token) runs before a token is issued. You can use it to edit the JWT.
+The [Custom Access Token Auth Hook](/docs/guides/auth/auth-hooks/custom-access-token-hook) runs before a token is issued. You can use it to edit the JWT.
 
 <Tabs
   scrollable

examples/slack-clone/nextjs-slack-clone-dotenvx/full-schema.sql

@@ -145,7 +145,7 @@ alter publication supabase_realtime add table public.users;
  */
 
 -- Create the auth hook function
--- https://supabase.com/docs/guides/auth/auth-hooks#hook-custom-access-token
+-- https://supabase.com/docs/guides/auth/auth-hooks/custom-access-token-hook
 create or replace function public.custom_access_token_hook(event jsonb)
 returns jsonb
 language plpgsql
@@ -221,4 +221,3 @@ begin
     return user_id;
 end;
 $$ language plpgsql;
-

examples/slack-clone/nextjs-slack-clone-dotenvx/supabase/migrations/20240214114147_auth-hook.sql

@@ -4,7 +4,7 @@
  */
 
 -- Create the auth hook function
--- https://supabase.com/docs/guides/auth/auth-hooks#hook-custom-access-token
+-- https://supabase.com/docs/guides/auth/auth-hooks/custom-access-token-hook
 create or replace function public.custom_access_token_hook(event jsonb)
 returns jsonb
 language plpgsql

examples/slack-clone/nextjs-slack-clone/full-schema.sql

@@ -145,7 +145,7 @@ alter publication supabase_realtime add table public.users;
  */
 
 -- Create the auth hook function
--- https://supabase.com/docs/guides/auth/auth-hooks#hook-custom-access-token
+-- https://supabase.com/docs/guides/auth/auth-hooks/custom-access-token-hook
 create or replace function public.custom_access_token_hook(event jsonb)
 returns jsonb
 language plpgsql
@@ -221,4 +221,3 @@ begin
     return user_id;
 end;
 $$ language plpgsql;
-

examples/slack-clone/nextjs-slack-clone/supabase/migrations/20240214114147_auth-hook.sql

@@ -4,7 +4,7 @@
  */
 
 -- Create the auth hook function
--- https://supabase.com/docs/guides/auth/auth-hooks#hook-custom-access-token
+-- https://supabase.com/docs/guides/auth/auth-hooks/custom-access-token-hook
 create or replace function public.custom_access_token_hook(event jsonb)
 returns jsonb
 language plpgsql

packages/shared-data/error-codes.ts

@@ -177,7 +177,7 @@ export const ERROR_CODES: Record<ErrorCodeService, Record<string, ErrorCodeDefin
         'Further MFA verification is rejected. Only returned if the MFA verification attempt hook returns a reject decision.',
       references: [
         {
-          href: 'https://supabase.com/docs/guides/auth/auth-hooks?language=add-admin-role#hook-mfa-verification-attempt',
+          href: 'https://supabase.com/docs/guides/auth/auth-hooks/mfa-verification-hook',
           description: 'MFA verification hook',
         },
       ],