[FEAT] : fixed Broken Real-Time SSE Dashboard Updates

[hrshjswniii]

Summary

This PR fixes the Server-Sent Events (SSE) real-time dashboard notification system. It adds connection registration logic to the stream API route, refactors the socket registry to support multi-tab synchronization via Sets, and resolves a database UUID lookup mismatch in the GitHub push webhook handler.

Closes #3129

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that changes existing behavior)
• 📝 Documentation update
• ♻️ Refactor / code cleanup (no functional change)
• ⚡ Performance improvement
• 🔒 Security fix
• 🧪 Tests only

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What Changed

• SSE Core Registry (src/lib/sse.ts):
  • Refactored sseConnections to map user UUIDs to a Set<ReadableStreamDefaultController> instead of a single controller. This supports multi-tab setups and prevents tabs from overriding or clearing active sockets.
  • Updated sendSSEEvent to push events to all active controllers in the user's Set and dynamically prune failed connections.
• Stream API Router (src/app/api/stream/route.ts):
  • Registered the active stream controller in the user's sseConnections Set during stream startup.
  • Safely deleted the controller from the user's Set in closeStream(), cleaning up empty registry keys.
• GitHub Webhook Handler (src/app/api/webhooks/github/route.ts):
  • Changed sendSSEEvent to dispatch push notification payloads using the resolved database user UUID (staleResult.userId) instead of the mutable githubLogin string.
• SSE Unit Tests (test/sse-stream-route.test.ts):
  • Added test cases verifying stream controller registration on connection, cleanup on disconnection, and concurrent tab tracking.

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How to Test

1. Run the stream route tests:

   node node_modules/vitest/vitest.mjs run test/sse-stream-route.test.ts

2. Verify that all 21 unit tests (including the 3 new connection lifecycle tests) pass successfully.

Expected result:
All tests pass cleanly.

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Checklist

• Linked the related issue above
• Self-reviewed my own diff
• No unnecessary console.log, debug code, or commented-out blocks
• npm run lint passes locally
• No TypeScript errors (npm run type-check)
• Added or updated tests where applicable
• Updated documentation / comments if behavior changed

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Additional Context

• The Set-based socket registry solves a key limitation of the original design where closing any browser tab terminated push events for all other active tabs.

[github-actions]

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