Separate structured logs from human-readable output

Move SetupLogger() to a standalone function called before config.Load()
so the logger is available from the very start. Replace all fmt.Printf
calls in config.go with slog calls. Redirect banner and endpoint info
to stderr, keeping stdout clean for structured log output (JSON/text).

Fixes #5

cmd/strix/main.go

@@ -36,18 +36,18 @@ Version: %s
 `
 
 func main() {
-	// Print banner
-	fmt.Printf(Banner, Version)
-	fmt.Println()
+	// Print banner to stderr so it doesn't mix with structured log output on stdout
+	fmt.Fprintf(os.Stderr, Banner, Version)
+	fmt.Fprintln(os.Stderr)
 
-	// Load configuration
-	cfg := config.Load()
-	cfg.Version = Version
-
-	// Setup logger
-	slogger, secrets := cfg.SetupLogger()
+	// Setup logger first, before anything else, so all messages use consistent format
+	slogger, secrets := config.SetupLogger()
 	slog.SetDefault(slogger)
 
+	// Load configuration (uses the logger for startup messages)
+	cfg := config.Load(slogger)
+	cfg.Version = Version
+
 	// Create adapter for our interface
 	log := logger.NewAdapter(slogger, secrets)
 
@@ -193,10 +193,10 @@ func printEndpoints(listen string) {
 	// ANSI escape codes for clickable link (OSC 8 hyperlink)
 	clickableURL := fmt.Sprintf("\033]8;;%s\033\\%s\033]8;;\033\\", url, url)
 
-	fmt.Println("\n🌐 Web Interface:")
-	fmt.Println("────────────────────────────────────────────────")
-	fmt.Printf("  Open in browser: %s\n", clickableURL)
-	fmt.Println("────────────────────────────────────────────────")
+	fmt.Fprintln(os.Stderr, "\nWeb Interface:")
+	fmt.Fprintln(os.Stderr, "────────────────────────────────────────────────")
+	fmt.Fprintf(os.Stderr, "  Open in browser: %s\n", clickableURL)
+	fmt.Fprintln(os.Stderr, "────────────────────────────────────────────────")
 
-	fmt.Println("\n📚 Documentation: https://github.com/eduard256/Strix")
+	fmt.Fprintln(os.Stderr, "\nDocumentation: https://github.com/eduard256/Strix")
 }