Prompt to recommend Dev Proxy Toolkit extension in .vscode/extensions.json when devproxyrc.json or devproxyrc.jsonc is detected

[garrytrinder]

Problem

When a devproxyrc.json or devproxyrc.jsonc file is detected in the current workspace, the toolkit should help projects recommend the Dev Proxy Toolkit extension for contributors.

Proposed Enhancement

• When detecting a devproxyrc.json or devproxyrc.jsonc in the workspace:
  1. Check if .vscode/extensions.json exists.
  2. If it exists, check if garrytrinder.dev-proxy-toolkit is included in the recommendations array.
  3. If the extension is not present in the array, or if the file does not exist, prompt the user asking if they want to add garrytrinder.dev-proxy-toolkit to the project's extension recommendations.

Benefits

• Ensures contributors are aware of and prompted to install the Dev Proxy Toolkit extension when working on relevant projects.
• Improves onboarding and reduces setup friction for new contributors.

Acceptance Criteria

• On detection of devproxyrc.json or devproxyrc.jsonc, checks for .vscode/extensions.json and presence of the extension in recommendations.
• If missing, prompts the user to optionally add the extension to recommendations.
• Minimal disruption to the user experience (no intrusive popups).