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>

pnpm-lock.yaml

@@ -930,9 +930,6 @@ importers:
 
   packages/core-trpc:
     dependencies:
-      "@repo/core-api":
-        specifier: workspace:*
-        version: link:../core-api
       "@tanstack/react-query":
         specifier: ^5.66.0
         version: 5.96.2(react@19.2.4)