feat: add cmake install and package export support

[esrrhs]

Summary

• Add standard CMake installation rules for target fakelua (shared library), flua (CLI tool), and public headers (fakelua.h).
• Generate and install CMake package configuration files (fakeluaConfig.cmake, fakeluaConfigVersion.cmake, fakeluaTargets.cmake) allowing downstream projects to use find_package(fakelua REQUIRED) and link fakelua::fakelua (or fakelua).
• Add fakelua.pc pkg-config configuration.
• Mark bundled CPM dependencies as EXCLUDE_FROM_ALL YES to avoid polluting the host system upon make install.
• Update README.md and README.zh.md with installation and CMake integration examples.

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.80%. Comparing base (e12a951) to head (a611bd3).
⚠️ Report is 2 commits behind head on master.
❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #19   +/-   ##
=======================================
  Coverage   87.80%   87.80%           
=======================================
  Files         119      119           
  Lines       24042    24042           
=======================================
  Hits        21109    21109           
  Misses       2933     2933           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.