Publish the Registry Stack extension for VS Code

[jeremi]

Tracked by #399. Depends on #394 and #393.

Outcome

VS Code users can install a Registry Stack extension that combines the existing schema-driven YAML experience with the shared project language server and common registryctl project actions.

Depends on the schema-driven baseline and shared Registry Stack language server.

Requirements

• Activate only when a workspace contains or opens a Registry Stack project.
• Integrate with the Red Hat YAML extension for normal YAML validation, completion, hover, outline, and formatting.
• Launch and supervise the shared Registry Stack language server.
• Discover a compatible registryctl installation or configured language-server binary.
• Report missing or incompatible binaries with an actionable installation/configuration message.
• Expose project commands for:
  • registryctl check;
  • offline registryctl test;
  • registryctl build.
• Never start live tests or read credentials implicitly.
• Display command output through standard VS Code progress/output/problem surfaces.
• Package for the Visual Studio Marketplace and Open VSX where policy and ownership allow.

Acceptance criteria

• Installing the extension in a clean supported VS Code environment enables the schema and language-server features for a sample project.
• The extension does not claim unrelated YAML files.
• Language-server startup, restart, crash, missing binary, and version mismatch paths are tested.
• Check, offline test, and build require an explicit user command and use the selected project/environment.
• No command logs secret values or full environment contents.
• Extension packaging is reproducible and has automated smoke tests on supported platforms.
• Installation, binary discovery, settings, and troubleshooting are documented.
• A release process and ownership location are documented before marketplace publication.

Non-goals

• Implementing project semantics in TypeScript
• Bundling a second copy of the Registry Stack compiler
• Automatically running live integration tests

[jeremi]

Review notes, verified against vscode-yaml and Marketplace policy (2026-07).

Prefer dynamic schema contribution over bundling. Bundled schemas (the yamlValidation contribution point) reintroduce extension-vs-CLI version skew. vscode-yaml exposes an extension API for schema contributors (registerContributor with requestSchema / requestSchemaContent); the extension can serve schema content straight from the discovered registryctl binary (registryctl authoring schema --kind ...), giving exact version match with zero drift, and fall back to the #394 snapshot when no binary is found. Confidence: medium-high that the API fits exactly this shape; verify early in implementation.

Add a migration AC. Define precedence when both the #394 workspace settings and the extension are present, and have the extension detect stale baseline settings and offer cleanup. Otherwise users get duplicate or conflicting validation.

Do not build publishing on PATs. Visual Studio Marketplace retires classic PAT publishing on 2026-12-01; build the publish pipeline on Entra ID workload identity from day one. Publish to Open VSX in parallel (that is how Cursor and other VS Code derivatives get the extension).

Small standard items: a "Restart language server" command, an output channel for server logs, and a trace-level setting. All cheap, and expected by users debugging setup issues.