Transform README from developer guide to user-focused extension store page

[Copilot]

The README contained build instructions, test procedures, and devcontainer configuration unsuitable for the VS Code Extension marketplace. Users browsing the extension store need usage documentation, not development setup.

Changes

• README.md: Rewritten as user-focused extension store page (252→123 lines)

  • Clear value proposition and feature highlights with visual indicators
  • Installation steps and usage workflows (tree view, command palette, context menu)
  • Requirements, limitations, and troubleshooting sections
  • Links to developer resources

• CONTRIBUTING.md: New file housing all developer content (265 lines)

  • Development setup, project structure, testing procedures
  • Build/packaging instructions, devcontainer configuration
  • Contribution guidelines and code standards
  • All technical content from original README preserved

Structure Comparison

Before: Single README with mixed audience

## Development
npm install
npm run compile
## Running unit tests  
NODE_PATH=./test/helpers mocha...
## Devcontainer: corporate TLS, CA certs...
[100+ lines of devcontainer config]

After: Separated by audience

• README.md → End users (features, installation, usage)
• CONTRIBUTING.md → Developers (setup, architecture, testing)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Create a README.md more suitable for the Extension store page</issue_title>
<issue_description>At the moment, the README.md is a developer guide, rather than a usage guide. It needs to be a usage guide instead, to be the front page for the extension store page.</issue_description>

<agent_instructions>Please have another go at this</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Create a README.md more suitable for the Extension store page #1

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[minouris]

I think it looks mostly okay. Nix the CONTRIBUTING.md, and put build instructions in a separate build instructions file.

"Recover deleted files and folders from VS Code's local history with just a few clicks. Never lose your work again!" - I thought I said no marketing speak, and no hyperbole? This is a stopgap tool, nothing more. They can still lose their work - why would we lie to the audience, just to get them to use a free extension? Are we that starved for validation?

[minouris]

Not sure I actually want contributors. If people want to change it, they can fork it.

[minouris]

@copliot act on review feedback