Add offset plane point-and-click user flow (#4552)

* Add a code mod for offset plane

* Add support for default plane selections to our `otherSelections` object

* Make availableVars work without a selection range
(because default planes don't have one)

* Make default planes selectable in cmdbar even if AST is empty

* Add offset plane command and activate in toolbar

* Avoid unnecessary error when sketching on offset plane by returning early

* Add supporting test features for offset plane E2E test

* Add WIP E2E test for offset plane
Struggling to get local electron test suite running properly

* Typos

* Lints

* Fix test by making it a web-based one:
I couldn't use the cmdBar fixture with an electron test for some reason.

* Update src/lib/commandBarConfigs/modelingCommandConfig.ts

* Update src/machines/modelingMachine.ts

* Revert changes to `homePageFixture`, as they were unused

* @Irev-Dev feedback: convert action to actor, fix machine layout

* Update plane icon to be not dashed, follow conventions closer

src/lib/toolbar.ts

@@ -252,10 +252,15 @@ export const toolbarConfig: Record<ToolbarModeName, ToolbarMode> = {
       [
         {
           id: 'plane-offset',
-          onClick: () =>
-            console.error('Plane through normal not yet implemented'),
+          onClick: ({ commandBarSend }) => {
+            commandBarSend({
+              type: 'Find and select command',
+              data: { name: 'Offset plane', groupId: 'modeling' },
+            })
+          },
+          hotkey: 'O',
           icon: 'plane',
-          status: 'unavailable',
+          status: 'available',
           title: 'Offset plane',
           description: 'Create a plane parallel to an existing plane.',
           links: [],