🧹 [code health improvement] Refactor nested networking operations

[Tcode-Motion]

🎯 What: Extracted inline TCP network callbacks into a dedicated stdlib/src/net/tcp.rs module.
💡 Why: Reduces the registration module footprint, decoupling core TCP setup/handling logic from the registration macro/function.
✅ Verification: Ran workspace formatting, checking, and tests successfully (ignoring unrelated existing compilation errors).
✨ Result: A cleaner module registration in stdlib/src/net.rs and more modular implementation of the std.net component.

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PR created automatically by Jules for task 5549435527509495314 started by @Tcode-Motion

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