feat(workload): normalize query demand and data evidence

[zzylol]

Summary

Adds normalized query-demand and data-evidence inputs without introducing lifecycle policy:

• explicit timestamps/durations;
• implicit-exact versus explicit accuracy requirements;
• latency requirements and predictability;
• one-time, fixed-interval, scheduled, estimated, and unknown recurrence;
• independent time scope and concrete time selection;
• at-rest/continuous/mixed/unknown data arrival;
• freshness-aware ingestion, cardinality, and distribution evidence;
• explicit root-to-normalized-workload-entry recurrence binding;
• PromQL and SQL frontend adaptation.

Lifecycle alternatives, legality, cost selection, E2E coverage, documentation, and export are separate follow-ups.

Verification

• cargo check --workspace --locked
• workload and frontend unit suites

Stack

• Base: test(planner): cover exact composition end to end #315
• Next: feat(lifecycle): enumerate summary maintenance alternatives #316