[LOW] Development mode logger hardcoded in production

## Description

`cmd/main.go:88-89`

```go
opts := zap.Options{
    Development: true,  // hardcoded
}
```

In development mode zap uses a more verbose encoder, enables DPanic-level panics, and uses a non-JSON format that is harder for log aggregators to parse.

## Fix

Default to `Development: false` for production. Make it configurable via a flag or environment variable.