feat(core-consent): add handlers and consentRouter tRPC router

Protocol-agnostic handlers (grant, withdraw, isGranted, getCategories)
in core-consent/handlers/ call IConsent methods and return typed results.

consentRouter uses a consent-specific tRPC context (userId + consentFactory)
so each procedure can resolve the per-user IConsent instance at call time.
Auth middleware guards all four procedures and maps UnauthenticatedError →
UNAUTHORIZED via defineErrorMiddleware from core-shared (no local duplicate).

76 tests passing; new handler and router code at 100% branch coverage.

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

packages/core-consent/package.json

@@ -14,7 +14,9 @@
     "test": "vitest run --passWithNoTests"
   },
   "dependencies": {
-    "@repo/core-shared": "workspace:*"
+    "@repo/core-shared": "workspace:*",
+    "@trpc/server": "^11.0.0",
+    "zod": "^3.24.0"
   },
   "peerDependencies": {
     "payload": "^3.0.0"