refactor(blog): factory-style use cases + per-use-case controllers + getArticleBySlug

- Use cases (create-article, get-articles, get-article-by-slug NEW) → factory functions
- Controllers split: articles.controller.ts → 3 single-responsibility files
- DI module wires factories with .toDynamicValue()
- tRPC router resolves controllers via container

Refactor log: §2, §3, §4.1, §4.2, §5.1
Spec: §6.2

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

packages/blog/src/integrations/api/router.test.ts

@@ -1,22 +1,18 @@
-import { beforeEach, describe, expect, it } from "vitest";
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import { blogContainer } from "../../di/container";
-import { BLOG_SYMBOLS } from "../../di/symbols";
-import { MockArticlesRepository } from "../../infrastructure/repositories/articles.repository.mock";
-import type { IArticlesRepository } from "../../application/repositories/articles.repository.interface";
+import { BlogModule } from "../../di/module";
 import { blogRouter } from "./router";
-import { articleFactory } from "../../__factories__/article.factory.js";
 
+// The router resolves controllers from blogContainer (a singleton).
+// We reload the module between tests to get a fresh MockArticlesRepository.
 describe("blogRouter", () => {
-  let repo: MockArticlesRepository;
-
   beforeEach(() => {
-    if (blogContainer.isBound(BLOG_SYMBOLS.IArticlesRepository)) {
-      blogContainer.unbind(BLOG_SYMBOLS.IArticlesRepository);
-    }
-    repo = new MockArticlesRepository();
-    blogContainer
-      .bind<IArticlesRepository>(BLOG_SYMBOLS.IArticlesRepository)
-      .toConstantValue(repo);
+    blogContainer.unbindAll();
+    blogContainer.load(BlogModule);
+  });
+
+  afterEach(() => {
+    blogContainer.unbindAll();
   });
 
   it("exposes articleBySlug, listArticles, createArticle procedures", () => {
@@ -26,19 +22,24 @@ describe("blogRouter", () => {
     expect(procedureNames).toContain("createArticle");
   });
 
-  it("articleBySlug returns the article when present", async () => {
-    await repo.createArticle(
-      articleFactory.build({ id: "1", title: "T", slug: "t", authorId: "u1" }),
-    );
-
-    const caller = blogRouter.createCaller({});
-    const result = await caller.articleBySlug({ slug: "t" });
-    expect(result?.id).toBe("1");
-  });
-
-  it("listArticles returns all articles when no input is given", async () => {
+  it("listArticles returns empty array by default", async () => {
     const caller = blogRouter.createCaller({});
     const result = await caller.listArticles();
     expect(result).toEqual([]);
   });
+
+  it("createArticle then articleBySlug returns the article", async () => {
+    const caller = blogRouter.createCaller({});
+
+    const created = await caller.createArticle({
+      title: "Router Test Article",
+      content: null,
+      authorId: "u1",
+      slug: "router-test",
+    });
+    expect(created.slug).toBe("router-test");
+
+    const fetched = await caller.articleBySlug({ slug: "router-test" });
+    expect(fetched.id).toBe(created.id);
+  });
 });