Fix CMake minimum version in test/C to unblock macOS CI

[Copilot]

macOS CI fails because newer CMake dropped compatibility with cmake_minimum_required versions below 3.5, and test/C/CMakeLists.txt was declaring VERSION 3.2.

Change

• test/C/CMakeLists.txt: Bump cmake_minimum_required from 3.2 → 3.5

# before
cmake_minimum_required(VERSION 3.2)

# after
cmake_minimum_required(VERSION 3.5)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Automatic tests are failing</issue_title>
<issue_description>Fails on MacOSX:

-- The C compiler identification is AppleClang 17.0.0.17000013
-- The CXX compiler identification is AppleClang 17.0.0.17000013
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Building libamtrack version 0.14.0+45-g8013279
-- Found GSL: /opt/homebrew/Cellar/gsl/2.8/include (found version "2.8")
CMake Error at test/C/CMakeLists.txt:1 (cmake_minimum_required):
  Compatibility with CMake < 3.5 has been removed from CMake.
-- Configuring incomplete, errors occurred!

  Update the VERSION argument <min> value.  Or, use the <min>...<max> syntax
  to tell CMake that the project requires at least <min> but has been updated
  to work with policies introduced by <max> or earlier.

  Or, add -DCMAKE_POLICY_VERSION_MINIMUM=3.5 to try configuring anyway.


Error: Process completed with exit code 1.
```</issue_description>

<agent_instructions>Cross check CI configuration for MacOSX, check also CMAKe stuff</agent_instructions>

## Comments on the Issue (you are @copilot in this section)

<comments>
</comments>

• Fixes Automatic tests are failing #280

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[Copilot]

Pull request overview

This PR unblocks macOS CI by updating the standalone C test project’s CMake minimum required version to a level supported by newer CMake releases.

Changes:

• Bump cmake_minimum_required in test/C/CMakeLists.txt from 3.2 to 3.5 to avoid configuration failure on newer CMake versions.

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