v0.5.0 — Per-agent content audit log

What's new

Per-agent content audit log — opt-in callback that records every content delivery to every agent, answering "what did this agent see and when?"

Features

• CCSStore(content_audit_log=callback) enables the audit log
• Five source types tracked: cache_hit, fetch, broadcast, write, search
• SHA-256 content hashes for cross-validation with the state log
• Gap-free sequence numbers shared across all agents and sources
• Version retention: historical artifact content preserved when audit is enabled
• Cross-validated instance_id shared between audit log and state log entries

Fixes (from code review)

• content_hash mismatch check now fires as a precondition before coordinator.commit(), not after
• Search audit callback wrapped in try/except with sequence number rollback
• get_content_at_version returns None on unknown artifact (was KeyError)
• Removed dead _record_search_view method (40 lines)

Documentation

• New "Content audit log" section in guide.md with schema reference
• Updated API reference with content_audit_log parameter
• README updated with v0.5 highlights

Testing

• 59 new tests across test_content_audit_log.py and test_ccsstore_content_audit.py
• End-to-end pipeline tests covering all 5 source types with broadcast strategy
• Cross-validation tests between audit log and state log entries

What's Changed

• [codex] docs(readme): add direction paragraph by @hipvlady in #5
• docs: restructure README for discovery-sprint audience by @hipvlady in #6

Full Changelog: v0.4.1...v0.5.0