Remove simple view functionality

[Copilot]

This PR removes the simple view functionality from the extension, which was only intended for debugging purposes.

The changes include:

• Removed the doc-detective.simpleView command registration from the extension
• Removed the simple view command from the package.json contributes section
• Removed the simple view command from the activationEvents in package.json
• Removed the menu entry for the simple view from the view/title section
• Removed the getSimpleView() method from the DocDetectiveWebviewViewProvider class
• Removed the getSimplifiedHtmlForWebview() method from the DocDetectiveWebviewViewProvider class
• Updated the fallback mechanism in the updateWebview() method to use the error view instead of the simple view
• Updated the test file to remove the assertion for the simpleView command
• Updated JSDoc comments to remove references to the simple view

The extension now uses only the standard view without any simplified view fallback, which helps streamline the codebase and remove debugging functionality that wasn't intended for production use.

Fixes #3.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}