Fix mixed numeric extrema

[mattfaltyn]

Summary

• compare mixed Int64, Float, and Double inputs to #min and #max by numeric value
• promote mixed numeric extrema to Double, matching Nemo's existing numeric promotion behavior
• preserve same-type and nonnumeric aggregate ordering
• cover every mixed numeric type pair, both magnitude orientations, and both input orders

Why

#min and #max compared StorageValueT directly. Its ordering groups values by storage variant, so mixed numeric aggregates could silently return the wrong value: for example, #min(10, 1.0) returned 10, while #max(10, 1.0) returned 1.0.

The fix is scoped to extrema aggregation so storage and sorting behavior that relies on the global StorageValueT ordering remains unchanged.

Fixes #805.

Testing

• cargo test --verbose
• RUSTFLAGS=-Dwarnings cargo clippy --all-targets --workspace --verbose
• cargo fmt --all -- --check
• RUSTFLAGS=-Dwarnings RUSTDOCFLAGS=-Dwarnings cargo doc --workspace
• cargo test --offline --workspace aggregates::processors::processor::test
• reproduced the original program through nemo-cli and confirmed min = 1.0, max = 10.0