Daemon mode for recv

[kwsantiago]

Problem

whisper recv reconnects on each invocation. For TUI or long-running scripts, this adds latency and wastes connections.

Solution

Add a daemon mode that maintains persistent relay connections:

# Start daemon (backgrounds, writes PID)
whisper daemon start

# Recv uses daemon's connection
whisper recv --via-daemon

# Stop daemon
whisper daemon stop

Implementation

• Daemon listens on Unix socket (e.g., $XDG_RUNTIME_DIR/whisper.sock)
• Maintains relay connections and subscriptions
• Clients connect to socket, request messages
• Daemon handles reconnection logic

Alternative: Simpler approach

Just add --persist flag to recv that reconnects automatically on disconnect:

whisper recv --persist  # reconnects forever until SIGTERM

This may be sufficient for most use cases without full daemon complexity.