Summary

Add ui/src/app/shared/mutations.ts with per-resource useMutation hooks, next to the queryOptions factories in shared/queries.ts, so each mutation owns its cache update.

Follow-up to #30338, raised in review of #30544.

Motivation

Pages migrated to react-query call services.<resource>.<mutation>() and then update the cache themselves with invalidateQueries or setQueryData. That pair is repeated at every call site, and more pages bring more copies. When a call site leaves out the cache update, or doesn't await it, the page keeps showing data from before the change.

Proposal

• One hook per resource (useProjectMutations(name), useClusterMutations(), useGpgKeyMutations()), wrapping useMutation, with the cache update in onSuccess.
• onSuccess returns the invalidation promise, so mutateAsync resolves after active queries have refetched.
• Error handling stays at the call site, keeping the existing per-action notifications.
• Use isPending instead of hand-rolled "updating" state.
• Move the pages already migrated (project details, clusters list/details, GnuPG keys) onto the hooks. Later migrations, starting with repositories and certificates, use them from the start.