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>

docs/library-decisions/2026-05-14-zod.md

@@ -6,7 +6,7 @@ decision: approved
 date: 2026-05-14
 deciders: [Danijel Martinek]
 adr: null
-lastRevalidated: null
+lastRevalidated: 2026-05-19
 is-sub-processor: false
 processes-pii: false
 filter-results: