⚡ Bolt: Avoid strings.ToLower allocation in header match

[callmeradical]

💡 What: Replaced strings.HasPrefix(strings.ToLower(...)) with strings.EqualFold(...) for case-insensitive prefix matching.
🎯 Why: strings.ToLower forces a memory allocation by returning a new string, which introduces unnecessary overhead in the hot path of handling proxy responses.
📊 Impact: Eliminates a string allocation per proxy response, reducing garbage collection pressure and CPU usage.
🔬 Measurement: Run a memory profile on the proxy under load; verify fewer string allocations.

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PR created automatically by Jules for task 6854397362403117504 started by @callmeradical

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