feat(while, vars, wait): add while subflow, variables block, wait block (#1754)

* Add variables block

* Add wait block

* While loop v1

* While loop v1

* Do while loops

* Copilot user input rerender fix

* Fix while and dowhile

* Vars block dropdown

* While loop docs

* Remove vars block coloring

* Fix lint

* Link docs to wait

* Fix build fail

apps/sim/serializer/types.ts

@@ -44,8 +44,9 @@ export interface SerializedLoop {
   id: string
   nodes: string[]
   iterations: number
-  loopType?: 'for' | 'forEach' | 'while'
+  loopType?: 'for' | 'forEach' | 'while' | 'doWhile'
   forEachItems?: any[] | Record<string, any> | string // Items to iterate over or expression to evaluate
+  whileCondition?: string // JS expression that evaluates to boolean (for while and doWhile loops)
 }
 
 export interface SerializedParallel {