Show offset planes in the scene, let user select them (#4481)

* Update offset_plane to actually create and show the plane in-engine

* Fix broken ability to use offsetPlanes in startSketchOn

* Make the newly-visible offset planes usable for sketching via UI

* Add a playwright test for sketching on an offset plane via point-and-click

* cargo clippy & cargo fmt

* Make `PlaneData` the first item of `SketchData` so autocomplete continues to work well for `startSketchOn`

* @nadr0 feedback re: `offsetIndex`

* From @jtran: "Need to call the ID generator so that IDs are stable."

* More feedback from @jtran and fix incomplete use of `id_generator` in last commit

* Oops I missed saving `isPathToNodeNumber` earlier 🤦🏻

* Make the distinction between `Plane` and `PlaneOrientationData` more clear per @nadr0 and @lf94's feedback

* Make `newPathToNode` less hardcoded, per @lf94's feedback

* Don't need to unbox and rebox `plane`

* A snapshot a day keeps the bugs away! 📷🐛 (OS: ubuntu-latest-8-cores)

* A snapshot a day keeps the bugs away! 📷🐛 (OS: windows-latest-8-cores)

* Rearranging of enums and structs, but the offsetPlanes are still not used by their sketches

* A snapshot a day keeps the bugs away! 📷🐛 (OS: ubuntu-latest-8-cores)

* A snapshot a day keeps the bugs away! 📷🐛 (OS: windows-latest-8-cores)

* Revert all my little newtype fiddling it's a waste of time.

* Update docs

* cargo fmt

* Remove log

* Print the unexpected diagnostics

* Undo renaming of `PlaneData`

* Remove generated PlaneRientationData docs page

* Redo doc generation after undoing `PlaneData` rename

* Impl FromKclValue for the new plane datatypes

* Clippy lint

* When starting a sketch, only hide the plane if it's a custom plane

* Fix FromKclValue and macro use since merge

* Fix to not convert Plane to PlaneData

* Make sure offset planes are `Custom` type

* SketchData actually doesn't need to be in a certain order
This avoids the autocompletion issue I was having.

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Adam Chalmers <adam.chalmers@zoo.dev>
Co-authored-by: Jonathan Tran <jonnytran@gmail.com>

src/lang/modifyAst.ts

@@ -19,6 +19,7 @@ import {
   ProgramMemory,
   SourceRange,
   sketchFromKclValue,
+  isPathToNodeNumber,
 } from './wasm'
 import {
   isNodeSafeToReplacePath,
@@ -526,6 +527,60 @@ export function sketchOnExtrudedFace(
   }
 }
 
+/**
+ * Modify the AST to create a new sketch using the variable declaration
+ * of an offset plane. The new sketch just has to come after the offset
+ * plane declaration.
+ */
+export function sketchOnOffsetPlane(
+  node: Node<Program>,
+  offsetPathToNode: PathToNode
+) {
+  let _node = { ...node }
+
+  // Find the offset plane declaration
+  const offsetPlaneDeclarator = getNodeFromPath<VariableDeclarator>(
+    _node,
+    offsetPathToNode,
+    'VariableDeclarator',
+    true
+  )
+  if (err(offsetPlaneDeclarator)) return offsetPlaneDeclarator
+  const { node: offsetPlaneNode } = offsetPlaneDeclarator
+  const offsetPlaneName = offsetPlaneNode.id.name
+
+  // Create a new sketch declaration
+  const newSketchName = findUniqueName(
+    node,
+    KCL_DEFAULT_CONSTANT_PREFIXES.SKETCH
+  )
+  const newSketch = createVariableDeclaration(
+    newSketchName,
+    createCallExpressionStdLib('startSketchOn', [
+      createIdentifier(offsetPlaneName),
+    ]),
+    undefined,
+    'const'
+  )
+
+  // Decide where to insert the new sketch declaration
+  const offsetIndex = offsetPathToNode[1][0]
+
+  if (!isPathToNodeNumber(offsetIndex)) {
+    return new Error('Expected offsetIndex to be a number')
+  }
+  // and insert it
+  _node.body.splice(offsetIndex + 1, 0, newSketch)
+  const newPathToNode = structuredClone(offsetPathToNode)
+  newPathToNode[1][0] = offsetIndex + 1
+
+  // Return the modified AST and the path to the new sketch declaration
+  return {
+    modifiedAst: _node,
+    pathToNode: newPathToNode,
+  }
+}
+
 export const getLastIndex = (pathToNode: PathToNode): number =>
   splitPathAtLastIndex(pathToNode).index