GCP connection and node setup UI gaps

Found while setting up a GCP oracle on dev (Task 9002, Operator org). Requirements: 1. Add connection (GCP): Region is required but sits under the collapsed "Advanced" section; pressing Create with it unset shows nothing until Advanced is opened. Show Region outside Advanced (or open Advanced on that error) so the refusal is visible. 2. Add node › Your Cloud: when no machine type is allowed for the connection's cloud, the Instance type list opens empty with no hint. Say so in the field ("No GCP types allowed") and, for the operator, link to Products › Instance types. Out of scope: NodeLink storage (Task 9002), allowed-type policy itself. Done means: - Vitest pins: the GCP connection dialog shows the Region error without expanding Advanced; Add node's empty instance-type state names the missing allowance. - Screenshot at 1280 and 390 of both states on the local stack.

Region moved out of Advanced, so its error shows without expanding; Add node's empty Instance type now says "No GCP types allowed." (operator: link to Products › Instance types). Vitest pins added; quick gate green; visual check at 1280/390 clean. PR #6652 queued to merge lane. Memory: none applied.