feat(sso): add social login providers (Google, GitHub, RoboLearn)

[mjunaidca]

Summary

• Add Google OAuth 2.0 social login via Better Auth built-in socialProviders
• Add GitHub OAuth social login via Better Auth built-in socialProviders
• Add RoboLearn SSO via genericOAuth plugin for custom OIDC integration
• All providers are environment-driven (toggle via env vars, no code changes needed)

Changes

Backend (sso-platform/src/lib/)

• auth.ts: Add conditional socialProviders block for Google/GitHub, add genericOAuth plugin for RoboLearn OIDC
• auth-client.ts: Add genericOAuthClient plugin for RoboLearn support

Frontend (sso-platform/src/components/)

• sign-in-form.tsx: Add social login buttons with SVG icons, handleSocialSignIn handler, loading states, error handling

Configuration

• .env.example: Add 10 new environment variables for social providers with setup instructions

Documentation

• docs/social-login-providers.md: Comprehensive guide covering:
  • Redirect URI patterns (different for built-in vs genericOAuth)
  • Setup instructions for each provider
  • Database & account linking behavior
  • Troubleshooting common errors

Key Implementation Details

Provider	Type	Callback Path
Google	Built-in	/api/auth/callback/google
GitHub	Built-in	/api/auth/callback/github
RoboLearn	genericOAuth	/api/auth/oauth2/callback/robolearn

Test Plan

• TypeScript compilation passes
• RoboLearn SSO tested and working
• Google OAuth (requires credentials)
• GitHub OAuth (requires credentials)

Environment Variables

# Google
GOOGLE_CLIENT_ID=...
GOOGLE_CLIENT_SECRET=...
NEXT_PUBLIC_GOOGLE_ENABLED=true

# GitHub
GITHUB_CLIENT_ID=...
GITHUB_CLIENT_SECRET=...
NEXT_PUBLIC_GITHUB_ENABLED=true

# RoboLearn
ROBOLEARN_CLIENT_ID=...
ROBOLEARN_CLIENT_SECRET=...
ROBOLEARN_SSO_URL=https://robolearn-sso.vercel.app/api/auth
NEXT_PUBLIC_ROBOLEARN_ENABLED=true

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR adds social login provider support to the Taskflow SSO Platform, enabling users to authenticate via Google OAuth, GitHub OAuth, and RoboLearn SSO (custom OIDC). The implementation leverages Better Auth's built-in socialProviders for Google and GitHub, and the genericOAuth plugin for RoboLearn's OIDC integration. All providers are environment-driven, allowing operators to enable/disable them via environment variables without code changes.

Key Changes:

• Added conditional social provider configuration to Better Auth using environment variables
• Implemented social sign-in UI with provider-specific buttons and icons in the sign-in form
• Created comprehensive documentation covering setup, redirect URIs, database behavior, and troubleshooting

Reviewed changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
sso-platform/src/lib/auth.ts	Added socialProviders block for Google/GitHub and conditional genericOAuth plugin for RoboLearn OIDC
sso-platform/src/lib/auth-client.ts	Added genericOAuthClient plugin to support RoboLearn on the client side
sso-platform/src/components/sign-in-form.tsx	Added social login buttons with SVG icons, handleSocialSignIn handler, OAuth parameter preservation, and error handling
sso-platform/docs/social-login-providers.md	Comprehensive guide covering redirect URI patterns, provider setup, database behavior, and troubleshooting
sso-platform/.env.example	Added 10 environment variables for social provider configuration with setup instructions
web-dashboard/src/app/page.tsx	Unrelated wording change in marketing copy ("revolutionizes" → "rethinks")
specs/008-social-login-providers/*	Complete specification, planning, and task tracking documents for the feature
history/prompts/008-social-login-providers/*	Prompt history documenting the development process including a redirect URI fix

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[Copilot]

The documentation describes an accountLinking configuration with trustedProviders that doesn't exist in the actual auth.ts file. This code block shows a configuration that is not present in the implementation.

Either:

1. Add the actual accountLinking configuration to auth.ts if account linking is needed
2. Update the documentation to reflect that Better Auth's default account linking behavior is being used
3. Clarify whether account linking is actually enabled by default in Better Auth

Without this configuration, the documented behavior (linking accounts with the same email across providers) may not work as described.

Suggested change

	```typescript
	accountLinking: {
	enabled: true,
	trustedProviders: ["google", "github", "robolearn"],
	}
	```
	> **Note:** Account linking is enabled by default in Better Auth. If a user logs in with multiple providers (Google, GitHub, RoboLearn) using the same email address, their accounts will be linked to a single user record automatically. No explicit configuration is required.

[Copilot]

The error handling in handleSocialSignIn only sets setIsLoading(false) in the catch block. However, if the social sign-in redirects successfully (which is the expected behavior), the loading state remains true forever.

While this might not cause visible issues (since the user is redirected away), it's better practice to ensure state cleanup happens in a finally block or remove the manual loading state reset entirely since the component will unmount on redirect.

Consider either:

1. Removing the setIsLoading(false) from the catch block since the redirect will unmount the component
2. Adding a finally block with setIsLoading(false) for consistency (though it won't execute on redirect)

Suggested change

	setErrors({ general: `Failed to sign in with ${provider}. Please try again.` });
	setErrors({ general: `Failed to sign in with ${provider}. Please try again.` });
	} finally {

[Copilot]

The error message format capitalizes the provider name inconsistently. For example, when the provider is 'google', the error message will read "Failed to sign in with google" instead of "Failed to sign in with Google".

Consider capitalizing the provider name in the error message:

setErrors({ general: `Failed to sign in with ${provider.charAt(0).toUpperCase() + provider.slice(1)}. Please try again.` });

Or create a mapping for display names:

const providerNames = { google: 'Google', github: 'GitHub', robolearn: 'RoboLearn' };
setErrors({ general: `Failed to sign in with ${providerNames[provider]}. Please try again.` });