fix(mobile): outline bar only while the keyboard is open

The indent/move bar above the keyboard stayed after the keyboard was
closed (back button) because the bullet kept its focus, and covered the
bottom navigation. useKeyboardInset now reports keyboardOpen by
comparing the visible height with the height without keyboard, which
works whether the browser shrinks the page or only the visual viewport.

Release v0.27.1.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "mindsift-frontend",
-  "version": "0.27.0",
+  "version": "0.27.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "mindsift-frontend",
-      "version": "0.27.0",
+      "version": "0.27.1",
       "license": "Unlicense",
       "dependencies": {
         "@fontsource-variable/inter": "5.3.0",