Add fish abbreviations for minikube-indri to plan docs

Step 0.12 update:
- Document ki, k9i, k9 abbreviations for quick kubectl/k9s access
- These avoid accidentally triggering work SAML flow

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

plans/k8s-migration.md

@@ -773,11 +773,18 @@ mise run indri-services-check
    The minikube cluster on indri is accessible from gilbert via direct connection.
    Cluster was created with `--apiserver-names=indri --listen-address=0.0.0.0`.
 
-   ```bash
-   # Switch to minikube context
-   kubectl config use-context minikube-indri
+   **Fish abbreviations** (in `~/.config/fish/config.fish`):
+   - `ki` → `kubectl --context=minikube-indri`
+   - `k9i` → `k9s --context=minikube-indri`
+   - `k9` → `k9s`
 
-   # Verify access
+   ```bash
+   # Quick access via abbreviations
+   ki get nodes
+   k9i
+
+   # Or explicitly set context
+   kubectl config use-context minikube-indri
    kubectl get nodes
    ```
    ```