proxy/config: create config package and migrate configuration (#329)

* proxy/config: create config package and migrate configuration

The configuration is become more complex as llama-swap adds more
advanced features. This commit moves config to its own package so it can
be developed independently of the proxy package.

Additionally, enforcing a public API for a configuration will allow
downstream usage to be more decoupled.

proxy/metrics_monitor.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/mostlygeek/llama-swap/event"
+	"github.com/mostlygeek/llama-swap/proxy/config"
 )
 
 // TokenMetrics represents parsed token statistics from llama-server logs
@@ -38,7 +39,7 @@ type MetricsMonitor struct {
 	nextID     int
 }
 
-func NewMetricsMonitor(config *Config) *MetricsMonitor {
+func NewMetricsMonitor(config *config.Config) *MetricsMonitor {
 	maxMetrics := config.MetricsMaxInMemory
 	if maxMetrics <= 0 {
 		maxMetrics = 1000 // Default fallback