Minor touchups for vortex-datafusion

[AdamGS]

Summary

Some minor touchups to the FileSource based DataFusion integration.

The two substantial changes here are:

1. When reading files, if we didn't have the footer in the cache, make sure to insert it. That can happen when using ListingTable without stats inference, or when using FileScanConfig directly in another table provider.
2. On write - move the schema-to-dtype logic outside of the loop. It only needs to happen once and the dtype is cloned per write task.

[codspeed-hq]

Merging this PR will not alter performance

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

⚡ 4 improved benchmarks
❌ 5 regressed benchmarks
✅ 1523 untouched benchmarks

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	decompress_rd[f64, (100000, 0.01)]	845.7 µs	981.3 µs	-13.82%
❌	Simulation	decompress_rd[f64, (100000, 0.1)]	845.7 µs	981.2 µs	-13.82%
❌	Simulation	encode_varbin[(1000, 4)]	143.2 µs	160.3 µs	-10.65%
❌	Simulation	encode_varbin[(1000, 8)]	143.9 µs	161 µs	-10.64%
❌	Simulation	encode_varbin[(1000, 32)]	148.8 µs	165.6 µs	-10.14%
⚡	Simulation	decompress_rd[f64, (100000, 0.0)]	1,024.4 µs	845.6 µs	+21.15%
⚡	Simulation	decompress_rd[f32, (100000, 0.0)]	586.7 µs	499.1 µs	+17.54%
⚡	Simulation	bitwise_not_vortex_buffer_mut[128]	244.4 ns	215.3 ns	+13.55%
⚡	Simulation	bitwise_not_vortex_buffer_mut[1024]	304.7 ns	275.6 ns	+10.58%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing adamg/df-minor-touchup-20260611 (1d7b1bd) with develop (1535ced)}

[joseph-isaacs]

This now has a cache!

[AdamGS]

where?

[robert3005]

what does Joe mean?