XY-1117: [ELF AMK P5] Add Work Journal capture schema and readback

[yvette-carlisle]

Summary

• Add source-adjacent Work Journal storage, service, HTTP, and MCP readback for session logs, handoff briefs, janitor reports, next steps, rejected options, source refs, and redaction.
• Keep journal content non-authoritative unless accepted Memory Authority or Dreaming Review refs resolve against storage.
• Add Work Journal spec, version registry entries, and drift evidence.

Validation

• cargo make fmt
• cargo make lint-fix
• cargo make checks
• cargo make check-docs
• git diff --check HEAD
• Focused DB-backed Work Journal acceptance command reported passing for current HEAD

Review

• Independent fresh-context read-only review checkpoint is clean for HEAD b8222b2.