Evaluate primitive predicates directly on encoded pages

[Xuanwo]

Goal

Evaluate supported primitive predicates directly on encoded pages when doing so is cheaper than decoding the predicate column to Arrow.

Context

Implementation and benchmark: #8661

Contract

• Support exact i32/u32 comparisons on Constant, RLE, and bitpacked pages.
• Select the encoded path independently per fragment from encoding, sampled selectivity, selected ranges, and predicted read amplification.
• Retain the ordinary decoded filter for unsupported or unfavorable cases.
• Stop encoded evaluation when bounded amplification or selected-range limits are exceeded.
• Short-circuit Constant outcomes only when metadata and nullability make the result exact.
• Preserve query results and fallback behavior for every unsupported encoding and predicate.

Completion gates

• perf: evaluate primitive predicates on encoded pages #8661 is reviewed and merged.
• Exact-result and fallback coverage passes across supported encodings, nullability, and fragmented inputs.
• Representative Local FS and object-storage measurements document accepted wins and rejected-path overhead.