Reuse attachment thread segment sanitizer in projection pipeline

- export and reuse `toSafeThreadAttachmentSegment` from `attachmentStore`
- align projection attachment path logic with store-safe thread IDs
- update projection pipeline tests to cover thread IDs with spaces
dadda0d490Julius Marminge committed on 3/2/2026, 2:49:25 AMparentfb92741
3 files changedLine totals unavailable