Add extension's landing page

[alefragnani]

Description

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Prerequisites Checklist

• The code is up-to-date with the master branch
• I have reviewed the CONTRIBUTING.md guidelines
• The code follows the repository's coding style (TypeScript conventions, formatting, naming)
• All changes are testable and have been manually tested

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Regular PR

If your PR is a regular PR, to fix an issue, provide a new feature or change a behavior, follow this additional checklist:

• This PR must address an existing issue

Changes Made

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Localization PR

If your PR is related to localization, follow this additional checklist:

• Identify the language code, like "pt-br" (There is no need to identify the language name)
• All UI strings have been added/updated to package.nls.json
• All translations were added/updated to the corresponding package.nls.<language>.json file(s)
• All new messages and strings located in extension source code have been added/updated to l10n/bundle.l10n.json
• All translations were added/updated to the corresponding l10n/bundle.l10n.<language>.json file(s)
• All walkthrough content has been added/updated to their Markdown files
• All translations were added/updated to the corresponding walkthrough/someStep.pt-br.md file(s)

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Testing

• Tested locally with the extension running in VS Code
• Tested on Windows (if applicable)
• Tested on macOS (if applicable)
• Tested on Linux (if applicable)
• Tested on Remotes (Containers, WSL, etc.)
• Verified existing functionality still works (no regressions)

Documentation

• Updated README.md if adding user-facing features (if applicable)

Additional Notes

[Copilot]

Pull request overview

This PR adds a GitHub Pages landing page for the Project Manager VS Code extension and updates the extension packaging ignore list so the new static site files aren’t bundled into the VSIX.

Changes:

• Added a new index.html marketing/landing page with sections for features, FAQ, and donation links.
• Added styles.css to style the landing page (layout, responsive header/nav, cards, and typography).
• Updated .vscodeignore to exclude the GH Pages entry files from extension packaging.

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated no comments.

File	Description
styles.css	Introduces the full styling for the new GitHub Pages landing page, including responsive layout and UI components.
index.html	Adds the landing page HTML structure and a small inline script for the mobile navigation toggle.
.vscodeignore	Excludes the GH Pages root files (index.html, styles.css) (and one page-only image) from the extension VSIX package.