refactor(logging): move logging setup to internal/logging

Moves logging configuration and setup to a dedicated package. Updates Config struct to use nested LoggingConfig. Updates main.go to use the new logging package.

internal/config/config_test.go

@@ -1,7 +1,6 @@
 package config
 
 import (
-	"log/slog"
 	"os"
 	"path/filepath"
 	"testing"
@@ -13,7 +12,8 @@ func TestLoad(t *testing.T) {
 	configFile := filepath.Join(tmpDir, "config.yaml")
 	
 	yamlContent := []byte(`
-log_level: "info"
+logging:
+  level: "info"
 server:
   host: "localhost"
   port: 8080
@@ -27,8 +27,8 @@ server:
 		if err != nil {
 			t.Fatalf("Load() error = %v", err)
 		}
-		if cfg.LogLevel != "info" {
-			t.Errorf("expected LogLevel 'info', got '%s'", cfg.LogLevel)
+		if cfg.Logging.Level != "info" {
+			t.Errorf("expected Logging.Level 'info', got '%s'", cfg.Logging.Level)
 		}
 		if cfg.Server.Host != "localhost" {
 			t.Errorf("expected Server.Host 'localhost', got '%s'", cfg.Server.Host)
@@ -39,11 +39,11 @@ server:
 	})
 
 	t.Run("Override from Env", func(t *testing.T) {
-		os.Setenv("TEST_LOG_LEVEL", "debug")
+		os.Setenv("TEST_LOGGING_LEVEL", "debug")
 		os.Setenv("TEST_SERVER_PORT", "9090")
 		os.Setenv("TEST_SERVER_HOST", "0.0.0.0")
 		defer func() {
-			os.Unsetenv("TEST_LOG_LEVEL")
+			os.Unsetenv("TEST_LOGGING_LEVEL")
 			os.Unsetenv("TEST_SERVER_PORT")
 			os.Unsetenv("TEST_SERVER_HOST")
 		}()
@@ -52,8 +52,8 @@ server:
 		if err != nil {
 			t.Fatalf("Load() error = %v", err)
 		}
-		if cfg.LogLevel != "debug" {
-			t.Errorf("expected LogLevel 'debug', got '%s'", cfg.LogLevel)
+		if cfg.Logging.Level != "debug" {
+			t.Errorf("expected Logging.Level 'debug', got '%s'", cfg.Logging.Level)
 		}
 		if cfg.Server.Port != 9090 {
 			t.Errorf("expected Server.Port 9090, got %d", cfg.Server.Port)
@@ -63,26 +63,3 @@ server:
 		}
 	})
 }
-
-func TestParseLogLevel(t *testing.T) {
-	tests := []struct {
-		input    string
-		expected slog.Level
-	}{
-		{"debug", slog.LevelDebug},
-		{"DEBUG", slog.LevelDebug},
-		{"info", slog.LevelInfo},
-		{"warn", slog.LevelWarn},
-		{"error", slog.LevelError},
-		{"unknown", slog.LevelInfo},
-		{"", slog.LevelInfo},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.input, func(t *testing.T) {
-			if got := ParseLogLevel(tt.input); got != tt.expected {
-				t.Errorf("ParseLogLevel(%q) = %v, want %v", tt.input, got, tt.expected)
-			}
-		})
-	}
-}