Agent Skills: hybrid-cloud-test-gen

Generate hybrid cloud tests for the Sentry codebase. Use when asked to "generate HC test", "create hybrid cloud test", "write HC test", "add HC test", "write RPC test", "test RPC service", "silo test", "cross-silo test", "outbox test", "API gateway test", or "endpoint silo test". Covers RPC service tests, API gateway tests, outbox pattern tests, and API endpoint tests with silo decorators.