XY-877: Add durable human decision requests for authority-boundary stops

[yvette-carlisle]

Summary

• add private authority decision request events linked to requires_human boundary checks
• extend manual_attention projection with public-safe decision request fields
• surface decision requests in status/evidence readback and document resume semantics

Validation

• cargo make fmt
• cargo make lint-fix
• cargo make test (1028 passed, 1 skipped)
• cargo test -p decodex boundary --all-features
• cargo test -p decodex tracker_tool_bridge --all-features
• cargo test -p decodex operator_status --all-features
• cargo test -p decodex agent_evidence --all-features