🧪 [testing improvement] Add Framebuffer::clear tests

[google-labs-jules]

🎯 What: The Framebuffer::clear method lacked test coverage. Added a new standalone unit test executable.
📊 Coverage: The new tests cover:

• Clearing with the default color (black).
• Clearing with a custom color.
• Out-of-bounds color clamping behavior.
• Proper resetting of the depth buffer to infinity.
  ✨ Result: Increased test coverage and confidence in the Framebuffer implementation, preventing regressions during future refactors.

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PR created automatically by Jules for task 3333166639687520322 started by @EricBorges2019

[google-labs-jules]

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