feat: add ProtonVPN extension - #373

[skifli]

ProtonVPN Extension

Adds a ProtonVPN extension that wraps the protonvpn CLI.

Page: Connect to Server	Page: VPN Settings	Page: VPN Status

Commands

• VPN Status - View connection status with server details in a split view. Quick connect/disconnect actions.
• Connect to Server - Browse countries and cities, quick connect, specialty servers, etc.
• VPN Settings - Toggle various ProtonVPN settings in Vicinae.

Features

• Dependency check - shows install instructions if protonvpn CLI is not found.
• Auth check - prompts to sign in if not authenticated.
• Split view on status page with connection details.
• Free plan support (paid features are greyed out with "Requires paid plan").

Testing

Tested locally on NixOS with protonvpn CLI installed.

Notes

• Settings that require a paid plan are shown but open the ProtonVPN pricing page if on free (and have a lock symbol).
• I only have a free plan so I haven't been able to test all the Pro feature toggles but they should work / if they do not its a small change to fix then.

[clankus-aurelius]

Thanks for contributing an extension to Vicinae! 👋

Before publication, this pull request receives two reviews:

1. An automated review for extension guidelines, safety, error handling, and likely correctness issues.
2. A final review from a Vicinae maintainer.

✅ Ready for human review. The automated reviewer approved the latest commit and a maintainer has been notified.

No blocking findings remain on the latest commit.

The automated reviewer examines only the current commit. New commits invalidate its previous decision and start another review.

[clankus-aurelius]

The extension introduces two misleading failure paths and an unrelated workspace dependency upgrade.

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Automated review found 1 publication-blocking issue.

This is an AI-generated first pass and may be mistaken. If a finding is unclear or incorrect, reply in the relevant thread and mention @aurelleb.

[clankus-aurelius]

All previously reported issues are resolved, and the follow-up changes introduce no new actionable problems.

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Automated extension review passed. A maintainer review is still required.

This is an AI-generated first pass and may be mistaken. If a finding is unclear or incorrect, reply in the relevant thread and mention @aurelleb.

[clankus-aurelius]

@aurelleb automated review passed for daa6087; this extension is ready for your review.

[skifli]

Oh also of note is the fact that I tried to in-build the login flow to Vicinae's UI - because I know that telling the user to go run a command in their own terminal to sign-in is a bit long. However, from a bit of testing, I believe the Proton VPN CLI reads directly from /dev/tty which means we cannot use piping etc.