Add production Docker deployment

Amp-Thread-ID: https://ampcode.com/threads/T-01a02485-5574-707c-bff4-5668d83bee8a
Co-authored-by: Heaust Azure <heaust.azure@gmail.com>

server/main.go

@@ -25,10 +25,17 @@ func run() error {
 		return err
 	}
 
-	log.Print("building core and handles packages")
-	packages, err := buildPackages(root)
+	packageDirectory := os.Getenv("YAWN_PACKAGES")
+	var packages map[string]memoryAsset
+	if packageDirectory == "" {
+		log.Print("building core and handles packages")
+		packages, err = buildPackages(root)
+	} else {
+		log.Printf("loading prebuilt packages from %s", packageDirectory)
+		packages, err = loadPackages(packageDirectory)
+	}
 	if err != nil {
-		return fmt.Errorf("build packages: %w", err)
+		return fmt.Errorf("prepare packages: %w", err)
 	}
 	log.Printf("loaded %d package assets into memory", len(packages))
 
@@ -84,6 +91,20 @@ func run() error {
 }
 
 func repositoryRoot() (string, error) {
+	if configured := os.Getenv("YAWN_ROOT"); configured != "" {
+		root, err := filepath.Abs(configured)
+		if err != nil {
+			return "", err
+		}
+		info, err := os.Stat(root)
+		if err != nil {
+			return "", err
+		}
+		if !info.IsDir() {
+			return "", fmt.Errorf("YAWN_ROOT is not a directory: %s", root)
+		}
+		return root, nil
+	}
 	directory, err := os.Getwd()
 	if err != nil {
 		return "", err