feat(asap-query-engine): support wider lookback windows over sliding precomputes

[milindsrivastava1997]

Summary

Closes #557 .

• Compose exact-multiple lookbacks from non-overlapping sliding precompute windows.
• Align evaluation timestamps down to the complete slide grid and fall back atomically when constituents are missing.
• Validate value/key grid compatibility for SetAggregator and DeltaSetAggregator. DeltaSetAggregator is accepted only when its tumbling window is a multiple of the sliding step and the sliding window is a multiple of the tumbling window.
• Update cleanup sizing for composed sliding windows.
• Add TDD coverage across instant, range, PromQL, SQL, and precompute-equivalence paths.

Validation

• cargo test -p query_engine_rust --lib
• cargo test -p asap_planner --lib
• cargo clippy -p query_engine_rust --lib --tests -- -D warnings
• Repository pre-commit hooks (format, check, clippy, tests)