feat: C/C++ API shared library targets

[0ax1]

Allow users to build and link against shared library targets for the C/C++ API:

target_link_libraries(cpp_target PRIVATE Vortex::cpp_shared)
target_link_libraries(c_target PRIVATE Vortex::ffi_shared)

To enable shared libs, enable: BUILD_SHARED_LIBS=ON.

As part of this, we switch to using shared libs on CI to cut down link time from static libs.

[codspeed]

Merging this PR will regress 1 benchmark

⚠️ 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
❌ 1 regressed benchmark
✅ 2193 untouched benchmarks
⏩ 218 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	WallTime	words_gather_scalar_avx2[65536]	8.3 µs	9.4 µs	-11.73%
⚡	WallTime	arrow_checked_add_u32_avx512[16384]	21.4 µs	17.6 µs	+21.51%
⚡	WallTime	arrow_checked_add_u32_avx2[16384]	21.4 µs	17.6 µs	+21.15%
⚡	WallTime	filtered_owned_i64_avx512[OneNullInEight]	26.3 µs	22.7 µs	+15.71%
⚡	WallTime	mul_i32_nonnull_avx512	7.9 µs	7.1 µs	+11.18%

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 ad/cxx-shared-lib (cd1c57b) with develop (fefcab0)²}

Footnotes

1. 218 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. ↩

2. No successful run was found on develop (a65c653) during the generation of this report, so fefcab0 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩