- Added deduplicateIncomingIssues() to consolidate content-identical issues
- DetectCollisions now deduplicates within incoming batch before processing
- Keeps issue with smallest ID when duplicates found
- Added comprehensive test suite in collision_dedup_test.go
- Export clean JSONL with bd-421 fix applied
Amp-Thread-ID: https://ampcode.com/threads/T-c17dd8bf-c298-4a80-baa5-55fa7c7bb9a3
Co-authored-by: Amp <amp@ampcode.com>