Sequentially scan Parquet files, process each row group in parallel

[brawer]

After this change, it takes 45 seconds on a MacBook Air 2026 with Apple M5 chip to find the best-scoring candidate in OpenStreetMap for every place in AllThePlaces. This time does not include the format conversion from OSM Protocol Buffers and AllThePlaces GeoJSON files to Parquet.

[coveralls]

Coverage Report for CI Build 26437041694

Coverage increased (+0.3%) to 94.19%

Details

• Coverage increased (+0.3%) from the base build.
• Patch coverage: 6 uncovered changes across 1 file (77 of 83 lines covered, 92.77%).
• 1 coverage regression across 1 file.

Uncovered Changes

File	Changed	Covered	%
src/diff_places.rs	59	53	89.83%
Total (3 files)	83	77	92.77%

Coverage Regressions

1 previously-covered line in 1 file lost coverage.

File	Lines Losing Coverage	Coverage
src/places/place_index.rs	1	99.25%

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Coverage Stats

Relevant Lines:	3477
Covered Lines:	3275
Line Coverage:	94.19%
Coverage Strength:	230.26 hits per line

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💛 - Coveralls