Remove sidebar menus in favor of lil' popovers (#3046)

* Convert user menu to a popover from a sidebar

* Move the user menu over to the left menu cluster

* Replace project sidebar with popover-style menu

* Styling tweaks, give export button a proper tooltip when disabled

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

* Filter orphan breaks, tweak space to remove mouse gaps

* Unify with and without avatar image code

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

* Rerun CI

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

* Rerun CI

* Prepare to move UserSidebarMenu over to right

* Revert AppHeader tweaks

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

* Rerun CI

* Fix typo in README

* Fix export E2E tests that relied on button text

* Missed the data-testid we used to have on the data-testid we had on the settings button

* Dang I missed another testId

* Update snapshots

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

* Rerun CI

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

src/components/UnitsMenu.tsx

@@ -25,11 +25,11 @@ export function UnitsMenu() {
           border border-solid border-chalkboard-10 dark:border-chalkboard-90 rounded
           shadow-lg`}
           >
-            <ul className="relative flex flex-col gap-0.5 items-stretch content-stretch">
+            <ul className="relative flex flex-col items-stretch content-stretch p-0.5">
               {baseUnitsUnion.map((unit) => (
                 <li key={unit} className="contents">
                   <button
-                    className="flex items-center gap-2 py-1 px-2 cursor-pointer hover:bg-chalkboard-20 dark:hover:bg-chalkboard-80 border-none text-left"
+                    className="flex items-center gap-2 m-0 py-1.5 px-2 cursor-pointer hover:bg-chalkboard-20 dark:hover:bg-chalkboard-80 border-none text-left"
                     onClick={() => {
                       settings.send({
                         type: 'set.modeling.defaultUnit',