fix: accept FixedSizeList dtype when deserializing ListValue scalars

[brancz]

Scalar serialization writes ScalarValue::Tuple as a protobuf ListValue for both List and FixedSizeList dtypes, but list_from_proto only accepted List. Since #8667 made constant detection unconditional, a constant fixed-size list column (e.g. UUIDs stored as fixed_size_list(u8)[16]) is compressed to a ConstantArray whose scalar metadata then fails to deserialize on read:

expected List dtype for ListValue, got fixed_size_list(u8)[16]

so files written this way come back unreadable. Scalar validation already handles FixedSizeList + Tuple (including the size check), so deserialization was the only gap.

Includes a proto round-trip test that fails without the fix.

[codspeed-hq]

Merging this PR will not alter performance

⚡ 3 improved benchmarks
❌ 2 regressed benchmarks
✅ 1614 untouched benchmarks
⏩ 42 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	rebuild_naive	91.4 µs	105.8 µs	-13.67%
❌	Simulation	chunked_varbinview_opt_canonical_into[(100, 100)]	305.6 µs	340.4 µs	-10.23%
⚡	Simulation	chunked_varbinview_into_canonical[(1000, 10)]	205.9 µs	170.1 µs	+21.08%
⚡	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 polarsignals:v0.77.0-patched (e855f4c) with develop (a6ce832)}

Footnotes

1. 42 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[codspeed-hq]

Unable to generate the performance report

There was an internal error while processing the run's data. We're working on fixing the issue. Feel free to contact us on Discord or at support@codspeed.io if the issue persists.