feat: add command context and diagnostics protocol

tests/facade.test.ts

@@ -39,9 +39,23 @@ test('disabled commands return a reason instead of mutating the document', () =>
   const before = facade.getState().document.version
   const state = facade.gui.command.getState('pad')
   assert.equal(state.status, 'enabled')
+  facade.selection.clear()
   facade.gui.workbench.setActive('Sketcher')
   const disabled = facade.gui.command.getState('pad')
   assert.equal(disabled.status, 'disabled')
-  assert.match(disabled.reason || '', /Part Design/)
+  assert.match(disabled.reason || '', /Part Design|compatible object/)
+  facade.gui.command.execute({ commandId: 'pad' })
+  assert.equal(facade.getState().diagnostics.at(-1)?.code, 'COMMAND_DISABLED')
   assert.equal(facade.getState().document.version, before)
 })
+
+test('command events carry a document-scoped request context', () => {
+  const facade = createMockFacade()
+  const events: string[] = []
+  let requestId = ''
+  facade.subscribe((event) => { events.push(event.type); if (event.type === 'command.started') requestId = event.context.requestId })
+  facade.gui.command.execute({ commandId: 'create-sketch' })
+  assert.ok(events.includes('command.started'))
+  assert.ok(events.includes('command.completed'))
+  assert.match(requestId, /^req-/)
+})