Update onboarding to be more complete (#551)

* Update Introduction

* Update Camera step

* Change link to expectations

Co-authored-by: Josh Gomez <114548659+jgomez720@users.noreply.github.com>

* Set outline for onboarding

* Add Streaming step

* Remove Units step

* Add default kcl script

* Add Code Editor step

* Add Parametric Modeling step

* Add Interactive Numbers step

* Update bracket to use sqrt

* Add Command K step

* Assuage @jessfraz's code itchies

* Add User Menu step

* Add Project Menu step

* Add Export step

* Improve error page to actually show error

* Update the sketch step

* Add Future Work section

* Bring back the bracket code on the final step

* Set up the code to the bracket when starting onboarding

* Fix missing import

* Don't throw away users code if not empty

* Prompt the user if they have content in their file

---------

Co-authored-by: Josh Gomez <114548659+jgomez720@users.noreply.github.com>

src/useStore.ts

@@ -18,6 +18,7 @@ import { EngineCommandManager } from './lang/std/engineConnection'
 import { KCLError } from './lang/errors'
 import { deferExecution } from 'lib/utils'
 import { _executor } from './lang/executor'
+import { bracket } from 'lib/exampleKcl'
 
 export type Selection = {
   type: 'default' | 'line-end' | 'line-mid'
@@ -409,7 +410,7 @@ export const useStore = create<StoreState>()(
             }, 100) as unknown as number
           )
         },
-        code: '',
+        code: bracket,
         setCode: (code) => set({ code }),
         deferredSetCode: (code) => {
           set({ code })