⚡ Optimize file extension check loop

[maattyi]

💡 What: Replaced the for loop that iterates through large_exts checking file extensions one-by-one with path.endswith(tuple(large_exts)) in src/proxy_server.py:645.

🎯 Why: The previous for loop iteration involves explicit Python-level jumps and method calls on each loop run. str.endswith natively supports multiple string matching using tuples executed entirely in C, eliminating the Python looping overhead.

📊 Measured Improvement:
A benchmark simulating calls to this block (100,000 iterations across 5 mixed URLs) yielded the following results:

• Baseline (Old Loop): 3.18040s
• Improvement (Inline Tuple): 0.94229s
  This represents an approximate ~3.3x speedup (70% reduction in execution time) for this specific code path.

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PR created automatically by Jules for task 15515563017442627226 started by @maattyi

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