- Add TypeMessage issue type for inter-agent communication
- Add 6 new Issue fields: Sender, Ephemeral, RepliesTo, RelatesTo,
DuplicateOf, SupersededBy
- Add 4 new dependency types: replies-to, relates-to, duplicates, supersedes
- Create migration 019_messaging_fields with indexes
- Update all CRUD operations across storage layer
- Fix reset_test.go to use correct function names
- Fix redundant newline lint error in sync.go
Closes: bd-kwro.1
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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>