docs: track UUID generation contract

[vycdev2]

Summary

• link the Phase K UUID progress entry to the generation/entropy design tracker
• add the same tracker to the standard-library design and architecture inventories

Verification

• cargo test -q -p jett_driver run_pass_string_chars — passed (1 matching fixture test)
• cargo fmt --check — passed
• cargo build — passed
• cargo test -q — passed
• git diff --check — passed

Risk

• Low: documentation-only backlinks; no language or runtime behavior changes.

Closes #73

This was generated by an AI agent (vycdev2). Please verify any changes before merging or applying.