feat v1.38.2: restore last space and editor mode across reloads

- LS_NAV stores {space, mode}; restored in setConfig from the cached
  config, with a retry after the live config when the cache was stale;
  deep-link hash wins; edit modes restored for admins only
- UX-MODES updated (owner reversed the 'always start in View' rule)
- smoke_nav_persist.mjs; TESTING/CHANGELOG same-commit

docs/UX-MODES.md

@@ -17,8 +17,11 @@ NO tab (since v1.30.2). The Background editor (v1.33.0) manages a purely visual
 decor layer (lines/rects/ovals/text in `space.decor`, drawn under the rooms,
 inert everywhere outside its editor).
 
-- **View** is the implicit default state: no editor tab is active. It is the only
-  state after every load (edit modes are never restored across reloads).
+- **View** is the implicit default state: no editor tab is active. Since
+  v1.38.2 the last space AND editor mode are restored across reloads
+  (localStorage, admins only for edit modes) — closing and reopening the tab
+  lands you where you were (owner's decision, reversing the earlier
+  "never restore" rule).
 - Activating an editor tab highlights it and opens that editor's bottom toolbar
   (both editors have one since v1.30.2). The toolbar and the active tab each
   carry an **X** that closes the editor back to View; re-clicking the active tab