Add resource form create feature and CreateResourceForm

[vyncent-t]

Summary

This PR introduces a form-based UI for creating Kubernetes resources, starting with Pods. Users can now create resources through a guided form accessible from both the sidebar "Create" button and the per-resource "Create Pod" button on the Pod list page, in addition to the existing YAML editor workflow.

Changes

• Added CreateResourceForm, reusable section-based base form template with titled sections and configurable fields
• Added CreatePodForm, extends the base form with Pod-specific fields organized into Metadata (name, namespace, labels) and Containers (container name, image, node name) sections
• Updated CreateButton (sidebar), added a "Create Form" toolbar button that opens a resource type picker modal, then the corresponding form (currently Pod)
• Updated CreateResourceButton (resource page), added a "Create Form" toolbar button that opens the Pod form directly
• Refactored both button components to use inner Activity content components (CreateActivityContent, CreateResourceActivityContent) so the form and editor share live React state
• Form applies merge into existing editor YAML, the form parses the current editor content, updates only form-managed fields, and preserves any extra fields the user added manually

Steps to Test

1. Navigate to the Pod list page
2. Click the "Create Pod" (+) button in the header
3. The YAML editor activity opens with the Pod base template
4. Click "Create Form" in the editor toolbar
5. Fill in Name, Namespace, Container Name, and Image fields
6. Click "Apply" and notice the editor YAML updates in-place with the form values, preserving other fields (ports, imagePullPolicy, etc.)
7. Click "Save & Apply" to create the Pod
8. Repeat from the sidebar "Create" button (click "Create Form", select "Pod" from the resource picker, fill the form, and verify the same behavior)

Screenshots (if applicable)

Create resource page and create form

Side button create form

[k8s-ci-robot]

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