Home page in desktop, separate file support (#252)

* Bugfix: don't toast on every change of defaultDir

* Refactor app to live under /file/:id

* Stub out Tauri-only home page

* home reads and writes blank files to defaultDir

* Fix initial directory creation

* Make file names editable

* Refactor onboarding to use normal fns for load issues

* Feature: load and write files to and from disk

* Feature: Add file deletion, break out FileCard component

* Fix settings close URLs to be relative, button types

* Add filename and link to AppHeader

* Style tweaks: scrollbar, header name, card size

* Style: add header, empty state to Home

* Refactor: load file in route loader

* Move makePathRelative to lib to fix tests

* Fix App test

* Use '$nnn' default name scheme

* Fix type error on ActionButton

* Fix type error on ActionButton

* @adamchalmers review

* Fix merge mistake

* Refactor: rename all things "file" to "project"

* Feature: migrate to <project-name>/main.kcl setup

* Fix tsc test

* @Irev-Dev review part 1: renames and imports

* @Irev-Dev review pt 2: simplify file list refresh

* @Irev-Dev review pt 3: filter out non-projects

* @Irev-review pt 4: folder conventions + home auth

* Add sort functionality to new welcome page (#255)

* Add todo for Sentry

src/App.test.tsx

@@ -1,5 +1,6 @@
 import { render, screen } from '@testing-library/react'
 import { App } from './App'
+import { describe, test, vi } from 'vitest'
 import { BrowserRouter } from 'react-router-dom'
 
 let listener: ((rect: any) => void) | undefined = undefined
@@ -12,12 +13,27 @@ let listener: ((rect: any) => void) | undefined = undefined
   disconnect() {}
 }
 
-test('renders learn react link', () => {
-  render(
-    <BrowserRouter>
-      <App />
-    </BrowserRouter>
-  )
-  const linkElement = screen.getByText(/Variables/i)
-  expect(linkElement).toBeInTheDocument()
+describe('App tests', () => {
+  test('Renders the modeling app screen, including "Variables" pane.', () => {
+    vi.mock('react-router-dom', async () => {
+      const actual = (await vi.importActual('react-router-dom')) as Record<
+        string,
+        any
+      >
+      return {
+        ...actual,
+        useParams: () => ({ id: 'new' }),
+        useLoaderData: () => ({ code: null }),
+      }
+    })
+    render(
+      <BrowserRouter>
+        <App />
+      </BrowserRouter>
+    )
+    const linkElement = screen.getByText(/Variables/i)
+    expect(linkElement).toBeInTheDocument()
+
+    vi.restoreAllMocks()
+  })
 })