Give a warning when using per-project default units (#5956)

* Give a warning when using per-project default units

Signed-off-by: Nick Cameron <nrc@ncameron.org>

* Factor non-settings out of MetaSettings

Signed-off-by: Nick Cameron <nrc@ncameron.org>

* Fix formatting

* Fix code pane e2e test

* Fix callstack blowup in edit flow

* Avoid dumb timeout issue with command registration in test

* Use a safer way to wait for modeling command registration in test

---------

Signed-off-by: Nick Cameron <nrc@ncameron.org>
Co-authored-by: Nick Cameron <nrc@ncameron.org>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Pierre Jacquier <pierre@zoo.dev>
Co-authored-by: Frank Noirot <frankjohnson1993@gmail.com>

e2e/playwright/code-pane-and-errors.spec.ts

@@ -21,14 +21,15 @@ test.describe('Code pane and errors', { tag: ['@skipWin'] }, () => {
     await page.addInitScript(() => {
       localStorage.setItem(
         'persistCode',
-        `// Extruded Triangle
-  sketch001 = startSketchOn(XZ)
-    |> startProfileAt([0, 0], %)
-    |> line(end = [10, 0])
-    |> line(end = [-5, 10])
-    |> line(endAbsolute = [profileStartX(%), profileStartY(%)])
-    |> close()
-  extrude001 = extrude(sketch001, length = 5)`
+        `@settings(defaultLengthUnit = in)
+// Extruded Triangle
+sketch001 = startSketchOn(XZ)
+  |> startProfileAt([0, 0], %)
+  |> line(end = [10, 0])
+  |> line(end = [-5, 10])
+  |> line(endAbsolute = [profileStartX(%), profileStartY(%)])
+  |> close()
+extrude001 = extrude(sketch001, length = 5)`
       )
     })