test(mainview): cover Exit design mode (sections 5 + 6) and refactor helpers

- Add sections 5 and 6 of the control-bar TODO as user-perspective
  integ tests: LP stays open after exit, sidebar+CCB+toolbar fits the
  window with a real editor gap, toolbar lands at innerWidth/2.5 when
  the toggle itself opened LP, sidebar never snaps wider than its
  capped render across the transition, toolbar respects
  livePanel.minWidth + iconsBar, and clicking #toolbar-go-live in
  design mode exits design mode + hides LP + shrinks the toolbar to
  the icon-bar-only width.
- Dedupe the suite's helpers: hoist WorkspaceManager, livePanel(),
  openLivePreview(), closeLivePreviewIfOpen(), enterDesignMode(),
  exitDesignMode(), resetBaseline() and the common beforeEach /
  afterEach to the top-level describe. Section describes now hold
  only the tests (plus a tiny section-5 baseline width pin).
- Fix duplicate "3." section numbering — the show-in-file-tree block
  is now "2a." to match the TODO md.
- Also include credits.md update.

Author: abose

src/thirdparty/licences/credits.md

@@ -18,3 +18,6 @@ Please find all other licenses and attributions below:
 
 ### https://onehtmlpagechallenge.com/
 * For the code samples in starter projects
+
+### https://seekicon.com/author/mariusz-ostrowski
+* For the undo redo icons used in the editor

test/control-bar-tests-todo.md

@@ -10,34 +10,6 @@ describe("mainview: central control bar + design mode", function () { … });
 Keep this file updated as we add coverage; remove lines as suites land.
 
 ---
-
-## 5. Exit design mode
-
-- [ ] Before flipping the body class, `sidebar.style.width` is pinned to the
-      currently rendered (max-width-capped) value so removing the cap
-      doesn't cause the sidebar to snap back to the stale uncapped width.
-- [ ] `Resizer.resyncSizer` runs after the pin so the handle follows.
-- [ ] Normal exit restores `#main-toolbar` to `savedToolbarWidth` (LP had
-      been open pre-collapse) or `innerWidth / 2.5` default (LP was opened by
-      the toggle itself). Never closes LP.
-- [ ] Exit clamps: sidebar + CCB + toolbar + 200 (min editor) ≤ window; if
-      the pre-collapse toolbar width would overflow, trim the sidebar first
-      and `data("resyncSizer")()` afterwards.
-- [ ] `livePanel.minWidth + iconsBar` lower bound is honored when picking
-      the restored toolbar width.
-- [ ] `$sidebar.data("maxsize")` is restored to its saved percentage.
-- [ ] `WorkspaceManager.isInDesignMode()` returns `false`, event fires with
-      `false`.
-
-## 6. Exit triggered by hiding live preview
-
-- [ ] Clicking `#toolbar-go-live` while in design mode:
-  - LP panel hides.
-  - `_restoreExpandedLayout` is called with `skipToolbarRestore: true`.
-  - `#main-toolbar` ends at the icon-bar-only width (WSM's
-    `_hidePluginSidePanel` width), not the pre-collapse LP size.
-  - `body.ccb-editor-collapsed` is removed.
-
 ## 7. Sidebar drag in design mode
 
 - [ ] Dragging the sidebar resizer rightward grows the sidebar linearly