Fix vMCP documentation based on cluster testing (#331)

* Fix VirtualMCPServer output columns in quickstart

Update expected kubectl output to match actual CRD printer columns:
- Change STATUS to PHASE
- Add BACKENDS and READY columns

Verified by testing against live cluster.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* Fix minimal VirtualMCPServer config to include required incomingAuth

The vMCP binary requires incomingAuth.type to be specified. Without it,
the pod crashes with: "incoming_auth.type must be one of: oidc, local,
anonymous"

Verified by testing against live cluster.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* Add note about optional clientSecretRef for token introspection

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

---------

Co-authored-by: Claude <[email protected]>

Author: jhrozek

docs/toolhive/guides-vmcp/configuration.mdx

@@ -10,7 +10,8 @@ complete field reference, see the
 ## Minimal configuration
 
 At minimum, a VirtualMCPServer requires a reference to an
-[MCPGroup](../tutorials/quickstart-vmcp.mdx#step-1-create-an-mcpgroup):
+[MCPGroup](../tutorials/quickstart-vmcp.mdx#step-1-create-an-mcpgroup) and an
+authentication type:
 
 ```yaml
 apiVersion: toolhive.stacklok.dev/v1alpha1
@@ -20,6 +21,8 @@ metadata:
 spec:
   groupRef:
     name: my-group
+  incomingAuth:
+    type: anonymous # Disables authentication; do not use in production
 ```
 
 The MCPGroup must exist in the same namespace and be in a Ready state before the
@@ -57,6 +60,7 @@ spec:
         issuer: https://your-idp.example.com
         audience: vmcp
         clientId: your-client-id
+        # For token introspection, add clientSecretRef referencing a Secret
 ```
 
 ### Kubernetes service account tokens

docs/toolhive/tutorials/quickstart-vmcp.mdx

@@ -159,8 +159,8 @@ kubectl get virtualmcpservers -n toolhive-system
 You should see output similar to:
 
 ```text
-NAME        STATUS   URL                                                              AGE
-demo-vmcp   Ready    http://vmcp-demo-vmcp.toolhive-system.svc.cluster.local:4483    30s
+NAME        PHASE   URL                                                            BACKENDS   AGE   READY
+demo-vmcp   Ready   http://vmcp-demo-vmcp.toolhive-system.svc.cluster.local:4483   2          30s   True
 ```
 
 :::info[What's happening?]