Task: Default to UDP/QUIC,

[orlandohohmeier]

Description

Set UDP/QUIC as the default transport for all Hypha internal communication (gateway, scheduler, workers, parameter servers). TCP should be opt‑in via configuration. The goal is to avoid subtle mismatches and take advantage of DCUtR and QUIC’s strengths for NAT traversal.

Acceptance Criteria

• Default configuration for all components (gateway, scheduler, workers) uses UDP/QUIC-only transports for internal communication.
• TCP remains supported but requires an explicit configuration
• Docs (including inline docs) only use QUIC in examples except for when we explain how to use TCP.