⚡ Bolt: Optimize JSON-RPC proxy payload parsing

[callmeradical]

💡 What: Replaced mime.ParseMediaType(resp.contentType) with strings.HasPrefix(resp.contentType, "text/event-stream") in the MCP client proxy hot path.
🎯 Why: mime.ParseMediaType performs parsing and multiple memory allocations (lowercasing strings, allocating parameter maps) on every single SSE response chunk. Because the proxy only cares about prefix-matching text/event-stream, a simple string prefix check eliminates this overhead and reduces GC pressure in a highly executed path.
📊 Impact: Reduces memory allocations and CPU overhead on every HTTP response processed by the proxy, speeding up streaming JSON-RPC delivery.
🔬 Measurement: Verify by running the test suite (go test ./...) to ensure SSE and normal responses are still routed correctly.

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PR created automatically by Jules for task 13712194356816598423 started by @callmeradical

[google-labs-jules]

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[callmeradical]

Closing as a duplicate/superseded Jules proposal. The canonical implementation is merged in #316.

[google-labs-jules]

Closing as a duplicate/superseded Jules proposal. The canonical implementation is merged in #316.

Understood. Acknowledging that this work is superseded by #316 and stopping work on this task.