refactor(registry): load runtime and service versions from JSON

Replace hardcoded string constants for Runtime and ServiceName types
with struct types loaded from an embedded registry.json file at init
time. This makes it possible to update supported versions without
code changes.

- Add registry.go and registry.json (embedded JSON data for all
  runtimes and services with their supported versions)
- Rewrite Runtime from string const to struct with Name, Type,
  Versions, Docs fields
- Rewrite ServiceName from string const to struct with Name, Type,
  Versions, Disk, Docs fields
- Update RuntimeForStack to look up runtimes by type string
- Update all callers to use runtime.Type string comparisons instead
  of const equality
- Remove version.go and generate_versions.go (superseded by registry)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

internal/question/build_steps.go

@@ -48,7 +48,7 @@ func (q *BuildSteps) Ask(ctx context.Context) error {
 				"pip install -r requirements.txt",
 			)
 		case models.Yarn, models.Npm:
-			if answers.Type.Runtime != models.NodeJS {
+			if answers.Type.Runtime.Type != "nodejs" {
 				if _, ok := answers.Dependencies["nodejs"]; !ok {
 					answers.Dependencies["nodejs"] = map[string]string{}
 				}

internal/question/build_steps_test.go

@@ -8,6 +8,15 @@ import (
 	"github.com/platformsh/platformify/internal/question/models"
 )
 
+func runtimeByType(t *testing.T, typ string) *models.Runtime {
+	t.Helper()
+	r, err := models.Runtimes.RuntimeByType(typ)
+	if err != nil {
+		t.Fatalf("runtime %q not found in registry", typ)
+	}
+	return r
+}
+
 func TestBuildSteps_Ask(t *testing.T) {
 	type args struct {
 		answers models.Answers
@@ -24,7 +33,7 @@ func TestBuildSteps_Ask(t *testing.T) {
 			q:    &BuildSteps{},
 			args: args{models.Answers{
 				Stack:              models.NextJS,
-				Type:               models.RuntimeType{Runtime: models.NodeJS, Version: "20.0"},
+				Type:               models.RuntimeType{Runtime: runtimeByType(t, "nodejs"), Version: "20.0"},
 				Dependencies:       map[string]map[string]string{},
 				DependencyManagers: []models.DepManager{models.Yarn},
 				Environment:        map[string]string{},
@@ -37,7 +46,7 @@ func TestBuildSteps_Ask(t *testing.T) {
 			q:    &BuildSteps{},
 			args: args{models.Answers{
 				Stack:              models.NextJS,
-				Type:               models.RuntimeType{Runtime: models.NodeJS, Version: "20.0"},
+				Type:               models.RuntimeType{Runtime: runtimeByType(t, "nodejs"), Version: "20.0"},
 				Dependencies:       map[string]map[string]string{},
 				DependencyManagers: []models.DepManager{models.Npm},
 				Environment:        map[string]string{},
@@ -50,7 +59,7 @@ func TestBuildSteps_Ask(t *testing.T) {
 			q:    &BuildSteps{},
 			args: args{models.Answers{
 				Stack:              models.GenericStack,
-				Type:               models.RuntimeType{Runtime: models.Ruby, Version: "3.3"},
+				Type:               models.RuntimeType{Runtime: runtimeByType(t, "ruby"), Version: "3.3"},
 				Dependencies:       map[string]map[string]string{},
 				DependencyManagers: []models.DepManager{models.Bundler},
 				Environment:        map[string]string{},
@@ -63,7 +72,7 @@ func TestBuildSteps_Ask(t *testing.T) {
 			q:    &BuildSteps{},
 			args: args{models.Answers{
 				Stack:              models.Rails,
-				Type:               models.RuntimeType{Runtime: models.Ruby, Version: "3.3"},
+				Type:               models.RuntimeType{Runtime: runtimeByType(t, "ruby"), Version: "3.3"},
 				Dependencies:       map[string]map[string]string{},
 				DependencyManagers: []models.DepManager{models.Bundler},
 				Environment:        map[string]string{},

internal/question/locations.go

@@ -24,7 +24,7 @@ func (q *Locations) Ask(ctx context.Context) error {
 			"allow":   true,
 		}
 	default:
-		if answers.Type.Runtime == models.PHP {
+		if answers.Type.Runtime.Type == "php" {
 			locations := map[string]interface{}{
 				"passthru": "/index.php",
 				"root":     "",

internal/question/models/answer.go

@@ -41,18 +41,21 @@ type Service struct {
 }
 
 type RuntimeType struct {
-	Runtime Runtime
+	Runtime *Runtime
 	Version string
 }
 
-func (t RuntimeType) String() string {
+func (t *RuntimeType) String() string {
+	if t.Runtime == nil {
+		return ""
+	}
 	if t.Version != "" {
 		return t.Runtime.String() + ":" + t.Version
 	}
 	return t.Runtime.String()
 }
 
-func (t RuntimeType) MarshalJSON() ([]byte, error) {
+func (t *RuntimeType) MarshalJSON() ([]byte, error) {
 	return json.Marshal(t.String())
 }