refactor(blog): unify use-case I/O schemas + presenter + feature error map

Per Plan 9 (spec R1-R28):
- Use cases: input + output schemas (getArticles, createArticle,
  getArticleBySlug). Output validated via outputSchema.parse before
  return. status field uses articleStatusSchema (was loose `string`).
- Controllers: receive `unknown`; safeParse with use-case schema;
  identity presenter (R11) on every controller.
- New integrations/api/procedures.ts with blogProcedure
  ([InputParseError → BAD_REQUEST], [ArticleNotFoundError → NOT_FOUND]).
- Router uses blogProcedure + .input(xInputSchema) for all 3 procedures.
- src/index.ts: remove articleBySlugQuery/listArticlesQuery re-exports;
  export schemas + types + IUseCase/IController aliases.
- src/ui/index.ts (NEW): query builders moved here; package.json adds
  ./ui subpath.
- New tests: R25 output-validation per use case; R26 router error-
  mapping (NOT_FOUND on missing slug, BAD_REQUEST on schema fail).

Refactor log: §1, §2, §3.1, §3.2, §3.3, §5.1, §5.2, §6.1, §6.2
Spec: R1–R6, R8–R15, R18–R20, R22–R26

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/blog/src/application/use-cases/get-articles.use-case.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it } from "vitest";
-import { getArticlesUseCase } from "@/application/use-cases/get-articles.use-case";
+import { ZodError } from "zod";
+import { getArticlesUseCase, getArticlesOutputSchema } from "@/application/use-cases/get-articles.use-case";
 import { MockArticlesRepository } from "@/infrastructure/repositories/articles.repository.mock";
 import { articleFactory } from "@/__factories__/article.factory";
 
@@ -10,7 +11,7 @@ describe("getArticlesUseCase", () => {
     await repo.createArticle(articleFactory.build({ id: "1", title: "A", slug: "a" }));
 
     const useCase = getArticlesUseCase(repo);
-    const result = await useCase();
+    const result = await useCase({});
     expect(result).toHaveLength(1);
     expect(result[0]?.id).toBe("1");
   });
@@ -27,3 +28,19 @@ describe("getArticlesUseCase", () => {
     expect(result[0]?.id).toBe("2");
   });
 });
+
+describe("getArticlesUseCase output validation (R25)", () => {
+  it("throws when the repository returns a malformed article", async () => {
+    const repo = new MockArticlesRepository();
+    // bypass the mock's createArticle (which is typed) by reaching into _articles directly
+    (repo as unknown as { _articles: unknown[] })._articles.push({ id: 123 });
+
+    const useCase = getArticlesUseCase(repo);
+    await expect(useCase({})).rejects.toBeInstanceOf(ZodError);
+  });
+
+  it("exports an output schema that mirrors Article[]", () => {
+    expect(getArticlesOutputSchema).toBeDefined();
+    expect(getArticlesOutputSchema.safeParse([]).success).toBe(true);
+  });
+});