feat(vscode-desktop): pre-install remote extensions

[Edd88-pixel]

Why

The VS Code Desktop wrapper could not pre-install remote extensions before the first desktop connection . This advances the extension pre-installation portion of #207 by bootstrapping the official stable remote server and delegating installation to vscode-desktop-core.

Changes

• add an optional validated extensions input while preserving the existing empty default
• adopt vscode-desktop-core v1.2.0 and pass the remote CLI, config, and extension paths
• download and validate the official stable VS Code Server only when its CLI is absent
• block ordinary workspace login while configured extensions are installed
• document extension configuration and bump the module version to v1.3.0
• cover defaults, validation, rendered configuration, and server reuse

Validation

• bun test registry/coder/modules/vscode-desktop/main.test.ts — 9 passed, 0 failed
• terraform validate -no-color — passed
• `terraform fmt -check for the changed Terraform files — passed
• real E2E with Coder v2.33.11

Description

Adds opt-in remote extension pre-installation to the VS Code Desktop module.

Type of Change

• New module
• New template
• Bug fix
• Feature/enhancement
• Documentation
• Other

Module Information

Path: registry/coder/modules/vscode-desktop
New version: v1.3.0
Breaking change: [ ] Yes [x] No

Testing & Validation

• Tests pass (bun test)
• Code formatted (bun fmt)
• Changes tested locally

Related Issues

Related to #207

[DevelopmentCats]

There are a couple things regarding the scorecard that can be addressed in a later PR but otherwiser this looks and works well

[matifali]

How do we ensure we are not installing an incompatible extension, since a user may be connecting from an older VS Code release that would download its own server?
AFAIK, VS Code downloads a matching server, not the latest.

It's still a good workaround, though. Let's add this to https://github.com/coder/coder/tree/main/dogfood/coder for dogfooding

[matifali]

Also @Edd88-pixel should #208 now be closed?

[Edd88-pixel]

@matifali Do you mean #207? #208 is already closed.

For #207, this PR covers the extension pre-installation part, but the settings input/application is still outstanding, so I'd keep it open unless we want to track that separately.

[Edd88-pixel]

Good point. The bootstrap server is isolated, so an older VS Code client can still install its own matching server. The part we don't currently guarantee is extension compatibility, since extensions are initially resolved using the stable bootstrap server.

Dogfooding this makes sense. We can follow up on that and test the behavior with older VS Code versions.

[matifali]

@matifali Do you mean #207? #208 is already closed.

For #207, this PR covers the extension pre-installation part, but the settings input/application is still outstanding, so I'd keep it open unless we want to track that separately.

Yes I mean #207