Implement VS Code Forma Workspace Foundation

Goal

Turn the command client into a safe, understandable Forma workspace experience before adding navigation or previews.

Sources

• architecture/editor-extension-adapter-contract
• design/editor-extension-mvp-design
• planning/editor-extension-alpha-13-execution-plan

In Scope

• Discover .forma.md at workspace-folder roots and as the nearest ancestor of an active Markdown document within the folder boundary.
• Support multiple discovered roots in VS Code multi-root workspaces and select the root applicable to the active document.
• Call config.inspect before treating a candidate root as ready.
• Watch relevant config changes and cancel or supersede stale refreshes.
• Model no-workspace, restricted, binary-missing, incompatible, invalid-config, checking, warning, failed, and ready states.
• Add the Forma status bar item, Output Channel, and Select Workspace, Inspect Configuration, Check Workspace, Refresh Workspace, and Open Output commands.
• Respect Workspace Trust at both manifest and runtime boundaries; reinitialize safe capabilities after trust is granted.
• Use workspace-extension placement so Forma executes beside local or remote workspace files.
• Handle unsupported virtual workspaces with a clear explanation.

Out Of Scope

• Reference providers.
• View preview or WebViews.
• Full remote-platform test matrix.
• Writable workspace commands.

Acceptance Criteria

• Root, nested, no-config, invalid, and multi-root discovery cases are covered by tests.
• Status and commands map deterministically from runtime state.
• Untrusted workspaces cannot execute configurable workspace binaries or Forma operations.
• Local workspace integration tests pass.
• The extension structure is compatible with remote workspace hosts and one feasible remote smoke is recorded when the local environment permits it.
• Remote SSH, Dev Containers, and WSL are not individually claimed as fully validated unless evidence exists.