feat(clerk-js): Add experimental combined flow (#4607)

Co-authored-by: Dylan Staley <88163+dstaley@users.noreply.github.com>
Co-authored-by: Bryce Kalow <bryce@clerk.dev>

Author: 3 people

.changeset/loud-balloons-grow.md

@@ -0,0 +1,7 @@
+---
+'@clerk/localizations': patch
+'@clerk/clerk-js': patch
+'@clerk/types': patch
+---
+
+Introduce experimental sign-in combined flow.

integration/presets/envs.ts

@@ -113,6 +113,15 @@ const withWaitlistdMode = withEmailCodes
   .setEnvVariable('private', 'CLERK_SECRET_KEY', instanceKeys.get('with-waitlist-mode').sk)
   .setEnvVariable('public', 'CLERK_PUBLISHABLE_KEY', instanceKeys.get('with-waitlist-mode').pk);
 
+const withCombinedFlow = withEmailCodes
+  .clone()
+  .setId('withCombinedFlow')
+  .setEnvVariable('private', 'CLERK_SECRET_KEY', instanceKeys.get('with-email-codes').sk)
+  .setEnvVariable('public', 'CLERK_PUBLISHABLE_KEY', instanceKeys.get('with-email-codes').pk)
+  .setEnvVariable('public', 'EXPERIMENTAL_COMBINED_FLOW', 'true')
+  .setEnvVariable('public', 'CLERK_SIGN_IN_URL', '/sign-in')
+  .setEnvVariable('public', 'CLERK_SIGN_UP_URL', '/sign-in');
+
 export const envs = {
   base,
   withEmailCodes,
@@ -129,4 +138,5 @@ export const envs = {
   withRestrictedMode,
   withLegalConsent,
   withWaitlistdMode,
+  withCombinedFlow,
 } as const;