Inspect provider integration revocation gate

Returns a read-only revocation gate for a connected app when the authenticated automation client has provider_integrations.manage. External URL: /v1/providers/current/integrations/{appId}/revocation-gate. Current Next.js implementation path: /api/platform/v1/providers/current/integrations/[appId]/revocation-gate. This read-only route does not require Idempotency-Key; it exposes terminal-state posture, fan-out targets, audit requirements, prerequisite evidence, and a fail-closed gate decision only. It never returns raw credentials, OAuth tokens, webhook secrets, raw sync payloads, customer PII, direct external-system calls, install mutations, pause/resume mutations, or revocation mutations.