Story: GitHub Integration (US-6)

[yashrastogi]

As a workspace member, I want to see my GitHub Issues and PRs assigned to me in my dashboard so that I can track development work alongside other notifications.

Acceptance Criteria

• User can connect GitHub account via OAuth
• Assigned issues and PRs appear as signals
• Status changes in GitHub reflect in Sentinent
• User can filter signals by GitHub specifically

Technical Scope

GitHub OAuth, polling/API webhooks, issue caching.