Content Identity System for Deduplication

Description

Implement the Content Identity system, which forms the foundation for data deduplication and redundancy tracking. It uses an adaptive hashing strategy to efficiently fingerprint files.

Implementation Notes

• The core logic is in src/domain/content_identity.rs.
• The ContentHashGenerator uses a fast, sampled BLAKE3 hash for large files (>100KB) and a full hash for smaller files, as described in the whitepaper.
• The corresponding content_identities table in the database schema stores these hashes.

Acceptance Criteria

• ContentHashGenerator can produce deterministic hashes for files.
• The system correctly uses different hashing strategies for small and large files.
• The database schema supports storing content hashes and linking them to entries.