feat: connect application input and output boundaries

tests/fixtures/typecheck/invalid-application-input.ts

@@ -0,0 +1,5 @@
+import type { ApplicationApi } from "../../../src/application/create-application.js";
+
+export const incompleteApplication: ApplicationApi = {
+  session: {} as ApplicationApi["session"],
+};

tests/fixtures/typecheck/invalid-application-output.ts

@@ -0,0 +1,7 @@
+import type { ApplicationOutputPorts } from "../../../src/application/create-application.js";
+
+export const invalidOutputPorts: ApplicationOutputPorts = {
+  session: {
+    getState: () => "signed-in",
+  },
+};