fix(cmake): add IOKit framework to APPLE link line

[LuciferYang]

Summary

The macOS arm64 consumer-smoke-test job has been failing on main since #24 with a long list of unresolved _IO* symbols (_IOObjectRelease, _IOServiceMatching, _IOHIDEventSystemClientCreate, _IORegistryEntryCreateCFProperty, …) — sample run: https://github.com/lance-format/lance-c/actions/runs/26272649710.

Root cause is plumbing, not the consumer example: sysinfo (pulled in transitively via the lance crates) calls IOKit on macOS for disk enumeration, CPU frequency, and thermal sensors, and objc2_io_kit declares the binding. Cargo's rustc-link-lib=framework=IOKit is honored when this repo builds, but a downstream consumer linking against the installed liblance_c.a via find_package(LanceC) (or pkg-config) only sees the frameworks we declare in our config files — and IOKit was missing.

Add -framework IOKit next to the existing CoreFoundation / Security / SystemConfiguration entries in all three mirroring places:

• CMakeLists.txt — build-tree LanceC_platform_deps interface library
• cmake/LanceCConfig.cmake.in — installed find_package(LanceC) consumers
• CMakeLists.txt — pkg-config Libs.private

Verification

Same cmake --install → examples/cmake-consumer build path the CI runs, on arm64 macOS (15.0 SDK, AppleClang 17):

$ cmake --install build --prefix _install
$ cmake -S examples/cmake-consumer -B consumer-build -DCMAKE_PREFIX_PATH="$PWD/_install"
$ cmake --build consumer-build
…
[100%] Built target consumer
$ consumer-build/consumer
usage: consumer <dataset_uri>
$ echo $?
2

Before the patch the same sequence dies at link with Undefined symbols for architecture arm64. After it, the link succeeds and the binary exits 2 (usage error) as the CI step expects.

After this lands

Unblocks the consumer-smoke macOS leg for every open PR — #42 (schema-evolution drop_columns) hits this exact failure on its CI run.

[LuciferYang]

cc @jja725 @Xuanwo

[jja725]

Thanks for the fix