fix: robust SSE parsing for multiline JSON and fallback handling

[harshav167]

Summary

Fixes SSE parsing issues when Codex API returns non-standard SSE formats.

Changes

• Handle data: with or without space after colon (both data: {...} and data:{...})
• Support multiline JSON split across multiple data: lines
• Graceful fallback chain: finalResponse → lastResponseLike → lastEvent
• Skip malformed JSON lines while preserving valid subsequent events
• Add tests for edge cases (no-space colon, multiline data)

Files Changed

• lib/request/response-handler.ts - Enhanced SSE parsing logic
• test/response-handler.test.ts - Added edge case tests

[numman-ali]

Thanks! I haven’t been able to reproduce yet. If you can share a failing raw SSE payload or ~/.opencode/logs/codex-plugin/request-*-response.json, I’ll validate and fold this in.