Polish operator dashboard presentation

[yvette-carlisle]

Summary

• refine dashboard typography, metric sizing, and operator copy
• simplify Projects into a compact table with active/all filtering and less dominant paths
• update dashboard assertions and operator-control-plane reference docs

Verification

• cargo test -p decodex operator_dashboard --all-features
• cargo test -p decodex operator_state_endpoint_serves_dashboard_html_from_root_and_dashboard_route --all-features
• cargo make fmt-check
• cargo make check-rust
• git diff --check