Add Go module, fail-fast config loader and /health endpoint

- go.mod: module code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest, go 1.25,
  sole dependency github.com/go-chi/chi/v5.
- internal/config: Load() reads MEALQUEST_* env vars and *_FILE secrets,
  collects every missing/invalid value into one error naming each variable,
  rejects inline secrets, and redacts secrets when formatted.
- internal/server: chi router serving GET /health -> {"status":"ok","version"}.
- cmd/server: wiring only; slog JSON logging, version via -ldflags
  "-X main.version=...", graceful shutdown on SIGINT/SIGTERM.
- .gitignore: cover .env*, deploy/secrets/, node_modules, dist, *.db.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

cmd/server/main.go

@@ -0,0 +1,74 @@
+// Command server runs the MealQuest HTTP service.
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/config"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/server"
+)
+
+// version is set at build time with -ldflags "-X main.version=<version>".
+var version = "dev"
+
+func main() {
+	cfg, err := config.Load()
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	logger := slog.New(slog.NewJSONHandler(os.Stdout, nil))
+	if err := run(cfg, logger); err != nil {
+		logger.Error("server stopped", "error", err)
+		os.Exit(1)
+	}
+}
+
+func run(cfg config.Config, logger *slog.Logger) error {
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer stop()
+
+	srv := &http.Server{
+		Addr:              cfg.HTTPAddr,
+		Handler:           server.NewRouter(logger, version),
+		ReadHeaderTimeout: 10 * time.Second,
+		ErrorLog:          slog.NewLogLogger(logger.Handler(), slog.LevelError),
+	}
+
+	errc := make(chan error, 1)
+	go func() {
+		logger.Info("listening",
+			"addr", cfg.HTTPAddr,
+			"public_url", cfg.PublicURL.String(),
+			"data_dir", cfg.DataDir,
+			"version", version,
+		)
+		errc <- srv.ListenAndServe()
+	}()
+
+	select {
+	case err := <-errc:
+		return err
+	case <-ctx.Done():
+	}
+
+	logger.Info("shutting down", "timeout", cfg.ShutdownTimeout.String())
+	shutdownCtx, cancel := context.WithTimeout(context.Background(), cfg.ShutdownTimeout)
+	defer cancel()
+	if err := srv.Shutdown(shutdownCtx); err != nil {
+		return fmt.Errorf("shutdown: %w", err)
+	}
+	if err := <-errc; !errors.Is(err, http.ErrServerClosed) {
+		return err
+	}
+	return nil
+}