Chore: Annotation store interface (#114100)

* annotation legacy store with api server, read only

* annotations are not addressable by ID for read operations

* add ownership for an app

* typo, of course

* fix go workspace

* update workspace

* copy annotation app in dockerfile

* experimenting with store interface

* finalising interfaces

* add tags as custom handler

* implement tags handler

* add missing config file

* mute linter

* update generated files

* update workspace

apps/annotation/pkg/app/app.go

@@ -30,6 +30,23 @@ func New(cfg app.Config) (app.App, error) {
 		},
 	}
 
+	// Add custom route handlers if a TagHandler is provided in SpecificConfig.
+	// The handler is created/owned by the registry layer and passed in via
+	// SpecificConfig to avoid the apps package depending on the registry.
+	if cfg.SpecificConfig != nil {
+		if annotationConfig, ok := cfg.SpecificConfig.(*AnnotationConfig); ok && annotationConfig.TagHandler != nil {
+			simpleConfig.VersionedCustomRoutes = map[string]simple.AppVersionRouteHandlers{
+				"v0alpha1": {
+					{
+						Namespaced: true,
+						Path:       "tags",
+						Method:     "GET",
+					}: annotationConfig.TagHandler,
+				},
+			}
+		}
+	}
+
 	a, err := simple.NewApp(simpleConfig)
 	if err != nil {
 		return nil, err

apps/annotation/pkg/app/config.go

@@ -0,0 +1,16 @@
+package app
+
+import (
+	"context"
+
+	"github.com/grafana/grafana-app-sdk/app"
+)
+
+// AnnotationConfig is the app-specific config for the annotation app. The
+// registry can pass a TagHandler implementation here to wire the /tags
+// resource route into the app without importing registry types.
+type AnnotationConfig struct {
+	// TagHandler is the handler function for the GET /tags custom route.
+	// The function signature matches app.CustomRouteHandler from the app-sdk.
+	TagHandler func(ctx context.Context, writer app.CustomRouteResponseWriter, request *app.CustomRouteRequest) error
+}