perf: cache table page metadata during memo eviction

[MichaReiser]

Cache the last resolved table page while evicting memo values, avoiding repeated page, vtable, memo-index, and type lookups for page-local victim streams. It slightly reduces the number of instructions on the eviction path for LRU, but it's a bigger impact for SIEVE where the eviction policy intentionally evicts items in their page order.

This keeps eviction policies storage-agnostic while preserving arbitrary ID ordering; the isolated sweep prototype improved by roughly 15%.

Benchmarks

Local benchmarks, because CodSpeed is bugged right now

Benchmark	#1234 on LRU	#1234 on SIEVE (#1226)
fast_path	−0.2%	+0.8%
fast_path_and_sweep	+0.6%	+0.4%
fill_and_evict	+0.4%	−0.1%
one_hit_wonders	−0.1%	−2.0%
phase_change	−0.1%	−0.9%
project_check_then_incremental	+1.1%	−0.1%
scan_resistance	−1.4%	−1.5%
Policy-specific instructions	−1.39%	−4.39%

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[codspeed-hq]

Merging this PR will not alter performance

✅ 74 untouched benchmarks
⏩ 1 skipped benchmark¹

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_{Comparing MichaReiser:optimize-memo-eviction-cursor (db905fe) with master (25ed9d3)}

Footnotes

1. 1 benchmark was skipped, so the baseline result was used instead. If it was deleted from the codebase, click here and archive it to remove it from the performance reports. ↩

[MichaReiser]

I'm leaning towards deleting this test