fix(core-consent): build consent router from the shared superjson t

The router previously created its own initTRPC without superjson while
the app router uses the shared transformer-enabled instance — a wire
transformer mismatch that corrupts inputs (audit finding A10). Procedures
now build on @repo/core-shared/trpc/init's t; a real client+fetch-adapter
round-trip test pins Date revival through appRouter-style mounting.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packages/core-consent/package.json

@@ -36,8 +36,10 @@
     "@repo/core-testing": "workspace:*",
     "@repo/core-typescript": "workspace:*",
     "@testing-library/react": "^16.0.0",
+    "@trpc/client": "^11.18.0",
     "@types/react": "^19.0.0",
     "@vitest/coverage-v8": "^3.2.7",
+    "superjson": "^2.2.1",
     "jsdom": "^25.0.0",
     "payload": "^3.14.0",
     "react": "^19.0.0",

packages/core-consent/src/consent.router.test.ts

@@ -1,9 +1,14 @@
 import { describe, it, expect, beforeEach } from "vitest";
 import { TRPCError } from "@trpc/server";
+import { fetchRequestHandler } from "@trpc/server/adapters/fetch";
+import { createTRPCClient, httpLink } from "@trpc/client";
+import superjson from "superjson";
 import { RecordingConsent } from "@repo/core-testing/instrumentation";
+import { router } from "@repo/core-shared/trpc/init";
 import { consentRouter } from "@/consent.router";
 import type { ConsentRouterContext } from "@/consent.router";
 import type { IConsent } from "@/consent.interface";
+import { InMemoryConsent } from "@/in-memory-consent";
 
 function makeContext(
   consent: RecordingConsent,
@@ -155,6 +160,77 @@ describe("consentRouter — auth checks", () => {
   });
 });
 
+describe("consentRouter — context guard", () => {
+  it("throws INTERNAL_SERVER_ERROR when consentFactory is missing from ctx", async () => {
+    const caller = consentRouter.createCaller({
+      userId: "user-1",
+    } as unknown as ConsentRouterContext);
+    await expect(caller.grant({ category: "analytics" })).rejects.toMatchObject(
+      {
+        code: "INTERNAL_SERVER_ERROR",
+        message: expect.stringContaining("consentFactory missing"),
+      },
+    );
+  });
+});
+
+describe("consentRouter — superjson wire round-trip (A10)", () => {
+  // The consent router MUST be built from the shared `t` (which is created
+  // with the superjson transformer). This test drives a real tRPC HTTP
+  // round-trip — client link + fetch adapter — so a transformer mismatch
+  // between the mounted router and the app client fails loudly here.
+  function makeClient(ctx: ConsentRouterContext) {
+    const appLikeRouter = router({ consent: consentRouter });
+    return createTRPCClient<typeof appLikeRouter>({
+      links: [
+        httpLink({
+          url: "http://localhost/api/trpc",
+          transformer: superjson,
+          fetch: (input, init) =>
+            fetchRequestHandler({
+              endpoint: "/api/trpc",
+              req: new Request(input, init as RequestInit),
+              router: appLikeRouter,
+              createContext: () => ctx,
+            }),
+        }),
+      ],
+    });
+  }
+
+  it("round-trips grant + getCategories, reviving Date fields", async () => {
+    const consent = new InMemoryConsent();
+    const client = makeClient({
+      userId: "user-1",
+      consentFactory: async () => consent,
+    });
+
+    const grantRes = await client.consent.grant.mutate({
+      category: "analytics",
+    });
+    expect(grantRes).toEqual({ success: true });
+
+    const { categories } = await client.consent.getCategories.query({});
+    expect(categories).toHaveLength(1);
+    expect(categories[0]!.category).toBe("analytics");
+    // superjson revives Dates across the wire; plain JSON would yield a string.
+    expect(categories[0]!.grantedAt).toBeInstanceOf(Date);
+  });
+
+  it("round-trips isGranted through the wire", async () => {
+    const consent = new InMemoryConsent();
+    const client = makeClient({
+      userId: "user-1",
+      consentFactory: async () => consent,
+    });
+    await client.consent.grant.mutate({ category: "marketing" });
+    const res = await client.consent.isGranted.query({
+      category: "marketing",
+    });
+    expect(res).toEqual({ granted: true });
+  });
+});
+
 describe("consentRouter — error passthrough", () => {
   it("propagates unmapped errors as INTERNAL_SERVER_ERROR", async () => {
     const brokenConsent: IConsent = {

packages/core-consent/src/consent.router.ts

@@ -1,5 +1,6 @@
-import { initTRPC } from "@trpc/server";
+import { TRPCError } from "@trpc/server";
 import { z } from "zod";
+import { t } from "@repo/core-shared/trpc/init";
 import { defineErrorMiddleware } from "@repo/core-shared/trpc/define-error-middleware";
 
 import type { ConsentFactory } from "./di/bind-production";
@@ -26,41 +27,57 @@ export type ConsentRouterContext = {
   consentFactory: ConsentFactory;
 };
 
-const tc = initTRPC.context<ConsentRouterContext>().create();
-
-const consentProcedure = tc.procedure
+/**
+ * Consent procedures build on the SHARED `t` instance from
+ * `@repo/core-shared/trpc/init` (audit finding A10): the app router is created
+ * with the superjson transformer, and a router built from a private `initTRPC`
+ * without superjson would corrupt every input/output that crosses the wire.
+ *
+ * The shared `t` is context-untyped, so the middleware narrows `ctx` to
+ * `ConsentRouterContext` at runtime — same cast pattern as the dsr router.
+ */
+const consentProcedure = t.procedure
   .use(defineErrorMiddleware([[UnauthenticatedError, "UNAUTHORIZED"]]))
   .use(async ({ ctx, next }) => {
-    if (!ctx.userId) throw new UnauthenticatedError();
-    return next();
+    const { userId, consentFactory } = ctx as Partial<ConsentRouterContext>;
+    if (!userId) throw new UnauthenticatedError();
+    if (!consentFactory) {
+      throw new TRPCError({
+        code: "INTERNAL_SERVER_ERROR",
+        message:
+          "consentFactory missing from tRPC context — wire the binding from " +
+          "bindProductionConsent/bindDevSeedConsent into createContext",
+      });
+    }
+    return next({ ctx: { ...ctx, userId, consentFactory } });
   });
 
-export const consentRouter = tc.router({
+export const consentRouter = t.router({
   grant: consentProcedure
     .input(grantHandlerInputSchema)
     .mutation(async ({ ctx, input }) => {
-      const consent = await ctx.consentFactory(ctx.userId!);
+      const consent = await ctx.consentFactory(ctx.userId);
       return grantHandler(consent, input);
     }),
 
   withdraw: consentProcedure
     .input(withdrawHandlerInputSchema)
     .mutation(async ({ ctx, input }) => {
-      const consent = await ctx.consentFactory(ctx.userId!);
+      const consent = await ctx.consentFactory(ctx.userId);
       return withdrawHandler(consent, input);
     }),
 
   isGranted: consentProcedure
     .input(isGrantedHandlerInputSchema)
     .query(async ({ ctx, input }) => {
-      const consent = await ctx.consentFactory(ctx.userId!);
+      const consent = await ctx.consentFactory(ctx.userId);
       return isGrantedHandler(consent, input);
     }),
 
   getCategories: consentProcedure
     .input(z.object({}).strict())
     .query(async ({ ctx }) => {
-      const consent = await ctx.consentFactory(ctx.userId!);
+      const consent = await ctx.consentFactory(ctx.userId);
       return getCategoriesHandler(consent);
     }),
 });