GenServer for async cache initialization with retry logic.

Uses handle_continue/2 pattern for non-blocking startup - the supervision tree completes immediately while cache initialization happens in the background.

Features

• Non-blocking startup: Application starts immediately regardless of API availability
• Partial failure handling: Some cache keys may succeed while others fail
• Automatic retry: Failed initialization retries with configurable backoff
• Status introspection: Check initialization status via initialized?/0 and status/0

Usage

The Warmer is started automatically by the supervision tree when autostart_cache is true. You can check its status:

Hyperliquid.Cache.Warmer.initialized?()
# => true or false

Hyperliquid.Cache.Warmer.status()
# => %{initialized: true, retry_count: 0, last_error: nil}