fix: render the view "Back" lands on after the popup is reopened (closes #268)

README.md

@@ -638,6 +638,21 @@ ExportPrivKey and ShowRecoveryPhrase — are deliberately absent from that list,
 so the popup can never reopen onto one of them with no password prompt in front
 of it.
 
+A reopened popup renders the wallet list and the one screen it restores onto,
+and nothing else, so every screen on the stack behind that one is still the
+blank template from `index.html`. "Back" therefore renders its target rather
+than only unhiding it, through the same dispatch and data guards as the restore
+(`src/popup/viewRouter.js`), and falls back to Home when the state the target
+would render is gone.
+
+It renders only a screen this page load has not rendered yet. Forward navigation
+renders as it goes, and `viewRouter.js` records every screen that reaches
+`showView()`, so "Back" onto a screen already on the page unhides it and nothing
+more — rendering it a second time would re-fetch and overwrite what it holds,
+such as an edit typed into Settings and not yet saved. Home is the one screen
+"Back" always re-renders, so the wallet list reflects anything that changed
+while the user was away from it.
+
 Every screen that holds secret material in the page registers a cleanup with
 `onViewLeave()` (`src/popup/views/helpers.js`), which `showView()` runs on every
 exit from that screen rather than only on its "Back" button, so nothing secret