bug: hide *Create Workspace* button for deleted workspaces

[cdr-robot]

Original Issue

From coder/coder#17417

The Create Workspace button is shown when filter:deleted:true, which doesn't work and shows a spinning window. The button should be hidden similar to what is done with deprecated:true.

Assignment

@coder

[github-actions]

❌ Failed to start the workspace. Please check the action logs for details.

[bpmct]

@coder

[github-actions]

✅ Coder workspace started! You can view the action logs here.

Workspace is available at: https://demo.coder.com/ben/issue-18

[cdr-robot]

I've implemented a fix for this issue in PR #41. The solution includes:

1. Hiding the 'Create Workspace' button when filter:deleted:true is applied to the workspaces page
2. Filtering out deleted templates from the templates dropdown in the workspace creation flow
3. Adding TypeScript type definitions for the deleted property which exists in the backend but wasn't properly exposed to the frontend

The PR has been created from the workspace at https://demo.coder.com/ben/issue-18