🧹 Code Health: Reduce complexity in drawChar

[google-labs-jules]

🎯 What: The drawChar function contained 4 levels of nested loops, and checked boundary conditions inside the inner loop for each drawn pixel. This was replaced by flattening the loops and computing the boundaries upfront based on scale and window dimensions. The repetitive float divisions to generate color were also moved out.
💡 Why: By minimizing nesting levels and inner-loop branching, the code is much cleaner, smaller, and easier to understand. The memory access pattern is also improved, making the drawing operation slightly more efficient.
✅ Verification: Reviewed math correctness. Compiled with cmake and tested with make tests and ./tests, everything passed as expected. Verified bounding behavior mathematically.
✨ Result: Improved readability and efficiency inside examples/viewer/main.cpp.

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PR created automatically by Jules for task 7832657396542246509 started by @EricBorges2019

[google-labs-jules]

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