Change GroupRef from bare string to typed struct for API consistency

[ChrisJBurns]

Summary

GroupRef is a bare string while every other cross-CRD reference in the API uses a typed struct. This inconsistency prevents extending GroupRef with additional fields (like namespace) without a breaking change, and blocks struct-level validation markers.

Severity: MUST FIX
Area: CRD API Design
Breaking: Yes — changes wire format from groupRef: "my-group" to groupRef: {name: "my-group"}

Location

• cmd/thv-operator/api/v1alpha1/mcpserver_types.go:295
• cmd/thv-operator/api/v1alpha1/mcpremoteproxy_types.go:130

Problem

GroupRef string `json:"groupRef,omitempty"`

Every other cross-CRD reference uses a typed struct:

• ExternalAuthConfigRef struct { Name string }
• ToolConfigRef struct { Name string }
• MCPOIDCConfigReference struct { Name, Audience, Scopes }
• EmbeddingServerRef struct { Name string }

GroupRef is the only one using a bare string.

Impact

• Inconsistent API pattern
• Cannot add fields like namespace to GroupRef without a breaking change
• No struct-level validation markers possible

Recommended Fix

1. Define type MCPGroupRef struct { Name string +""+json:"name"+""+ }
2. Replace GroupRef string with GroupRef *MCPGroupRef on MCPServerSpec and MCPRemoteProxySpec
3. Update controller code to access GroupRef.Name instead of GroupRef directly
4. This is a breaking wire-format change (from string to object) — must happen before v1beta1