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 message boundaries.

Changes Made

• Added VIRTIO_VSOCK_F_SEQPACKET feature flag support
• Implemented SOCK_SEQPACKET socket type handling in vsock implementation
• Added socket type validation to ensure host UDS matches vsock socket type
• Enhanced connection logic to handle SEQPACKET connections appropriately

Why This Change

This addresses GitHub Issue #4822 by enabling VMs to relay datagrams over vsock while maintaining packet boundaries, which is not possible with SOCK_STREAM that combines messages together. This provides a more efficient solution than implementing custom packet boundaries within stream sockets.

Testing

Verified that:

• SOCK_SEQPACKET connections can be established successfully
• Socket type mismatches are properly rejected
• Message boundaries are preserved in SEQPACKET mode

Fixes #4822

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This PR was created from task: https://cloud.blackbox.ai/tasks/Nuype64zWauLUuobO0u01