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/integrations/api/router.test.ts

@@ -1,7 +1,8 @@
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
-import { blogContainer } from "../../di/container";
-import { BlogModule } from "../../di/module";
-import { blogRouter } from "./router";
+import { TRPCError } from "@trpc/server";
+import { blogContainer } from "@/di/container";
+import { BlogModule } from "@/di/module";
+import { blogRouter } from "@/integrations/api/router";
 
 // The router resolves controllers from blogContainer (a singleton).
 // We reload the module between tests to get a fresh MockArticlesRepository.
@@ -24,7 +25,7 @@ describe("blogRouter", () => {
 
   it("listArticles returns empty array by default", async () => {
     const caller = blogRouter.createCaller({});
-    const result = await caller.listArticles();
+    const result = await caller.listArticles({});
     expect(result).toEqual([]);
   });
 
@@ -43,3 +44,36 @@ describe("blogRouter", () => {
     expect(fetched.id).toBe(created.id);
   });
 });
+
+describe("blogRouter (R26 error mapping)", () => {
+  beforeEach(() => {
+    blogContainer.unbindAll();
+    blogContainer.load(BlogModule);
+  });
+
+  afterEach(() => {
+    blogContainer.unbindAll();
+  });
+
+  it("translates ArticleNotFoundError → NOT_FOUND", async () => {
+    const caller = blogRouter.createCaller({});
+    try {
+      await caller.articleBySlug({ slug: "missing" });
+      throw new Error("expected throw");
+    } catch (e) {
+      expect(e).toBeInstanceOf(TRPCError);
+      expect((e as TRPCError).code).toBe("NOT_FOUND");
+    }
+  });
+
+  it("translates zod parse failure → BAD_REQUEST", async () => {
+    const caller = blogRouter.createCaller({});
+    try {
+      await caller.articleBySlug({} as unknown as { slug: string });
+      throw new Error("expected throw");
+    } catch (e) {
+      expect(e).toBeInstanceOf(TRPCError);
+      expect((e as TRPCError).code).toBe("BAD_REQUEST");
+    }
+  });
+});