⚡ Bolt: [performance improvement] Remove intermediate allocations

[cloudesize67-cmd]

💡 What:

• Replaced string-based splits (.split("\n")) with char-based splits (.split('\n')) in xdk-build/src/python.rs.
• Removed .collect::<Vec<&str>>().into_iter() and iterated directly over the .split() iterator in xdk-build/src/python.rs.
• Avoided collecting parts into a Vec by using pattern matching on .next() calls in xdk-build/src/python.rs.
• Replaced .collect::<Vec<_>>().join("") with .collect::<String>() in xdk-lib/src/casing.rs.
• Added inline comments explaining these optimizations.

🎯 Why: These changes eliminate unnecessary intermediate heap allocations (Vecs) and string cloning, leading to a faster and more efficient execution path, especially in frequently called parsing or logging routines.

📊 Impact: Reduces memory usage and CPU cycles by removing intermediate object creation and collection phases during string manipulations. The operations are now done entirely via lazy iterators or direct accumulation into the final String.

🔬 Measurement: Verified with cargo clippy --all --all-targets --all-features (to ensure the optimizations are idiomatic) and make test-generator (to ensure no functional regressions were introduced).

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PR created automatically by Jules for task 8310679001457643873 started by @cloudesize67-cmd

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