refactor(core-trpc): break the core-api package cycle

core-trpc imported AppRouter (type-only) from core-api, which depends
on the features, which depend on core-trpc — a cycle that killed every
turbo graph walk (lint/build/CI) and an illegal core -> core-composition
boundary edge. The tRPC context is now router-agnostic (AnyTRPCRouter);
useTRPC takes the router type as a generic and each feature exports a
type-only app-slice (e.g. BlogAppSlice) mirroring its mount key, so UI
hooks keep full procedure typing without touching the composition layer.

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

packages/navigation/src/integrations/api/router.ts

@@ -9,14 +9,22 @@ import type { IGetHeaderController } from "../../interface-adapters/controllers/
 import { navigationProcedure } from "./procedures";
 
 export const navigationRouter = router({
-  header: navigationProcedure
-    .input(getHeaderInputSchema)
-    .query(({ input }) => {
-      const ctrl = navigationContainer.get<IGetHeaderController>(
-        NAVIGATION_SYMBOLS.IGetHeaderController,
-      );
-      return ctrl(input);
-    }),
+  header: navigationProcedure.input(getHeaderInputSchema).query(({ input }) => {
+    const ctrl = navigationContainer.get<IGetHeaderController>(
+      NAVIGATION_SYMBOLS.IGetHeaderController,
+    );
+    return ctrl(input);
+  }),
 });
 
 export type NavigationRouter = typeof navigationRouter;
+
+/**
+ * This feature's slice as it is mounted in the app router (the `navigation` key
+ * in @repo/core-api). UI hooks pass it to `useTRPC<NavigationAppSlice>()` so
+ * they stay fully typed without core-trpc (or this feature's client code)
+ * depending on the composition layer. Type-only: erased at compile time.
+ */
+export type NavigationAppSlice = ReturnType<
+  typeof router<{ navigation: typeof navigationRouter }>
+>;

packages/navigation/src/ui/hooks/use-header.ts

@@ -2,10 +2,11 @@
 
 import { useSuspenseQuery } from "@tanstack/react-query";
 import { useTRPC } from "@repo/core-trpc";
+import type { NavigationAppSlice } from "../../integrations/api/router";
 
 // eslint-disable-next-line @typescript-eslint/explicit-function-return-type
 export function useHeader() {
-  const trpc = useTRPC();
+  const trpc = useTRPC<NavigationAppSlice>();
   return useSuspenseQuery(trpc.navigation.header.queryOptions({})) as {
     data: {
       items: { label: string; href: string; external: boolean }[];