[015] Auto-select the fastest proxy from configured entries

[konard]

Parent epic: #1

Phase: Connectivity Layer
Priority: 15

Scope

Select the best configured proxy based on recent health and latency checks with deterministic fallback behavior.

Implementation Steps

• Track health, latency, and failure windows for each configured proxy.
• Rank eligible proxies without leaking secrets to logs or telemetry.
• Add tests for tie-breaking, failure cooldowns, and direct fallback.

Acceptance Criteria

• Proxy selection prefers healthy low-latency routes.
• Selection is deterministic when proxy metrics tie.
• Users can disable automatic proxy switching.

Automation

Generated from #1 using scripts/decompose-epic.mjs.