Update configuration source controls

configuration_sources_test.go

@@ -37,7 +37,7 @@ func TestCollectionInputLoadsNativeImportsAndLaterOverride(t *testing.T) {
 	directory := t.TempDir()
 	mainPath := filepath.Join(directory, "collection.yaml")
 	defaultsPath := filepath.Join(directory, "defaults.yaml")
-	if err := os.WriteFile(mainPath, []byte("configkit:\n  imports:\n    - path: defaults.yaml\n"), 0o600); err != nil {
+	if err := os.WriteFile(mainPath, []byte("config:\n  imports:\n    - path: defaults.yaml\n      required: true\n"), 0o600); err != nil {
 		t.Fatal(err)
 	}
 	if err := os.WriteFile(defaultsPath, []byte("prompts:\n  greeting:\n    version: imported\n    messages:\n      - role: user\n        content: Hello\n    output:\n      format: text\n      validation_mode: none\n"), 0o600); err != nil {
@@ -65,7 +65,7 @@ func TestCollectionInputLoadsNativeImportsAndLaterOverride(t *testing.T) {
 
 func TestCollectionInputLoadsEmbeddedImportsAndLaterOverride(t *testing.T) {
 	files := fstest.MapFS{
-		"collection.yaml": {Data: []byte("configkit:\n  imports:\n    - path: defaults.yaml\n")},
+		"collection.yaml": {Data: []byte("config:\n  imports:\n    - path: defaults.yaml\n      required: true\n")},
 		"defaults.yaml":   {Data: []byte("prompts:\n  greeting:\n    version: imported\n    messages:\n      - role: user\n        content: Hello\n    output:\n      format: text\n      validation_mode: none\n")},
 	}
 	filesystem := configkit.NewFilesystem("embedded collection", files)

docs/roadmap/implementation.md

@@ -217,6 +217,13 @@ maintained example assets; application resource shape can still be transitional.
 Validation: use the existing source-helper/import tests when runnable; otherwise
 record remaining resource-shape dependencies. Leave source headers for Stage 3.
 
+Completion: source-root import controls now use `config`, with the selected
+file imports explicitly required. Reviewed source-evidence assertions and found
+no obsolete API or main-layer spellings in use. Validation passed: the native
+and embedded collection input tests, directory/filesystem source-helper tests,
+and inherited imported-content test on Go 1.27.0; `git diff --check` passed.
+Resource formats and headers remain for the following assignments.
+
 ## Stage 3: Introduce Identified Record Shapes And Header Version 2
 
 Scope: schema types and loader definition in `internal/configuration/load.go`.

examples/go-library/prepare/collections/support/collection.yaml

@@ -1,5 +1,6 @@
 version: "1"
-configkit:
+config:
   imports:
     - path: fragments/resources.yaml
+      required: true
 release_version: "1.4.0"

internal/configuration/prompts_test.go

@@ -16,7 +16,7 @@ import (
 
 func TestLoadCapturesInheritedImportedContent(t *testing.T) {
 	files := fstest.MapFS{
-		"app/main.yaml":         {Data: []byte("configkit:\n  imports:\n    - path: ../catalog/base.yaml\n    - path: ../other/definition.yaml\ncollections:\n  docs:\n    prompts:\n      child:\n        extends: base\n")},
+		"app/main.yaml":         {Data: []byte("config:\n  imports:\n    - path: ../catalog/base.yaml\n      required: true\n    - path: ../other/definition.yaml\n      required: true\ncollections:\n  docs:\n    prompts:\n      child:\n        extends: base\n")},
 		"catalog/base.yaml":     {Data: []byte("collections:\n  docs:\n    release_version: r1\n    prompts:\n      base:\n        version: \"v1\"\n        messages:\n          - role: ' USER '\n            cache_control:\n              type: ' ephemeral '\n              ttl: ' 1h '\n            content_file: ./body.md\n        output:\n          format: text\n          validation_mode: basic\n")},
 		"catalog/body.md":       {Data: []byte("Captured {{.name}}")},
 		"other/definition.yaml": {Data: []byte("collections:\n  other:\n    prompts:\n      child:\n        messages:\n          - role: user\n            content_file: ./body.md\n        output:\n          format: text\n          validation_mode: none\n")},