feat: 기능 추가 과정중

src/application/ports/in/application-api.ts

@@ -1,7 +1,18 @@
-import type { SessionState } from "../auth-session-port.js";
-import type { StoragePort } from "../storage-port.js";
+import type { SessionState } from "../auth-session-port.ts";
+import type { StoragePort } from "../storage-port.ts";
 
-export type { SessionState } from "../auth-session-port.js";
+export type { SessionState } from "../auth-session-port.ts";
+
+/**
+ * Features add their driving API through module augmentation. The application
+ * owns the registry contract without importing any concrete feature.
+ */
+export interface ApplicationFeatureInputs {}
+
+export type ApplicationFeatureId = Extract<
+  keyof ApplicationFeatureInputs,
+  string
+>;
 
 export type ColorSchemePreference = "system" | "light" | "dark";
 
@@ -54,7 +65,9 @@ export type ApplicationApi = Readonly<{
     >;
   }>;
   features: Readonly<{
-    has(featureId: string): boolean;
-    get(featureId: string): unknown;
+    has(featureId: string): featureId is ApplicationFeatureId;
+    get<FeatureId extends ApplicationFeatureId>(
+      featureId: FeatureId,
+    ): ApplicationFeatureInputs[FeatureId];
   }>;
 }>;