feat(skel): add cmd/minstrel entrypoint

Parses --config / SMARTMUSIC_CONFIG, loads YAML config with env overlay,
initializes slog, starts the chi HTTP server, and shuts down cleanly on
SIGINT/SIGTERM.

cmd/minstrel/main.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"flag"
+	"fmt"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"git.fabledsword.com/bvandeusen/minstrel/internal/config"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/logging"
+	"git.fabledsword.com/bvandeusen/minstrel/internal/server"
+)
+
+func main() {
+	if err := run(); err != nil {
+		fmt.Fprintf(os.Stderr, "minstrel: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+func run() error {
+	configPath := flag.String("config", os.Getenv("SMARTMUSIC_CONFIG"), "path to YAML config file")
+	flag.Parse()
+
+	cfg, err := config.Load(*configPath)
+	if err != nil {
+		return fmt.Errorf("load config: %w", err)
+	}
+
+	logger, err := logging.New(os.Stdout, cfg.Log.Level, cfg.Log.Format)
+	if err != nil {
+		return fmt.Errorf("init logger: %w", err)
+	}
+
+	logger.Info("minstrel starting",
+		"address", cfg.Server.Address,
+		"log_level", cfg.Log.Level,
+		"log_format", cfg.Log.Format,
+	)
+
+	srv := server.New(logger)
+	httpServer := &http.Server{
+		Addr:              cfg.Server.Address,
+		Handler:           srv.Router(),
+		ReadHeaderTimeout: 10 * time.Second,
+	}
+
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+
+	errCh := make(chan error, 1)
+	go func() {
+		logger.Info("listening", "address", cfg.Server.Address)
+		if err := httpServer.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+			errCh <- err
+		}
+		close(errCh)
+	}()
+
+	select {
+	case <-ctx.Done():
+		logger.Info("shutdown signal received")
+	case err := <-errCh:
+		if err != nil {
+			return fmt.Errorf("server: %w", err)
+		}
+	}
+
+	shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	if err := httpServer.Shutdown(shutdownCtx); err != nil {
+		return fmt.Errorf("shutdown: %w", err)
+	}
+	logger.Info("minstrel stopped")
+	return nil
+}