Add plan parent-reduction rule API

[joseph-isaacs]

Summary

• add a typed PlanParentReduceRule API for child-driven physical-plan rewrites
• add a type-erased adapter for collecting heterogeneous typed rules
• add an ordered static PlanParentRuleSet whose first successful rewrite wins
• verify in debug builds that rewrites preserve the parent row count and dtype
• expose the framework through vortex_layout::plan::optimizer

Stack

This draft is stacked on #9142 and targets vortex-plan.

The concrete expression optimization rules are intentionally excluded and live in #9166, which is stacked on this PR.

Scope

This PR only introduces the rule framework and APIs. It registers no concrete rules and does not change optimization behavior.

Checks

• cargo test -p vortex-layout — 211 passed
• cargo clippy -p vortex-layout --all-targets --all-features -- -D warnings
• cargo +nightly fmt --all -- --check
• git diff --check

[codspeed-hq]

Hooray! CodSpeed harness just leveled up!

The base and head of this comparison were measured with different runner settings, so their benchmark values are not directly comparable.

What changed between base and head:

• CodSpeed runner v5 changed how benchmarks are measured (base 5.0.1 → head 4.13.0). View release notes
• Cycle estimation (on → off) changes how benchmark performance is calculated. Learn more about cycle estimation

Re-run the base with the same settings to get a valid performance comparison.

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_{Comparing vortex-plan-rules (ed09b04) with vortex-plan (bd412f3)}