feat: Add SEQPACKET socket type support for vsock

[sumansaurabh]

Summary

Implements SEQPACKET socket type support for virtio vsock to enable datagram relay use cases while preserving packet boundaries.

Changes

• Added SEQPACKET socket type handling in vsock implementation
• Enhanced socket type validation to ensure host UDS matches vsock socket type
• Updated connection logic to support both SOCK_STREAM and SOCK_SEQPACKET
• Added proper error handling for socket type mismatches

Motivation

This change addresses the need for VMs to relay datagrams over vsock while maintaining packet boundaries, which SOCK_STREAM cannot provide as it combines packets together. The VIRTIO_VSOCK_F_SEQPACKET feature is part of the virtio specification v1.2.

Testing

• Verified SEQPACKET socket creation and connection
• Tested socket type validation between vsock and host UDS
• Ensured backward compatibility with existing SOCK_STREAM functionality

Fixes #4822

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This PR was created from task: https://cloud.blackbox.ai/tasks/aXNtIycyRzvQrn_QJWmGj