Merge branch 'feat/layout-test'

Merge branch 'feat/layout-test'

feat: icon language for export destinations + bigger, rotating caret

Two more rounds of live feedback on the popup export picker:
- The selector's caret was too small to read as a toggle. Now bigger
  (10px -> 15px) and rotates 180 degrees while the menu is open.
- Calling out "Copy to clipboard" by name made the other rows' silent
  destination (file download vs. external upload) feel unexplained by
  contrast. Added a small non-translated inline SVG icon to every quick
  button and menu row: download-arrow for file exports, copy-icon for
  clipboard-bound ones, upload-arrow for Gist/Notion -- matching the
  "up" cue Gist/Notion already implied.

Icons are plain <svg> markup outside any data-i18n span, so future
wording tweaks never touch translations again. Correspondingly stripped
the symbols that used to be baked into translated strings themselves
(popupBtnExportAll's leading arrow, popupBtnGist/popupBtnNotion's
trailing arrow, popupBtnCopyHtml shortened to "Copy"), re-translated
across all 26 locales. 300 passed, 0 failed.

version bump: 0.4.28.1

version bump: 0.4.28.0

aaarg .4

bump

version bump

fix: stale pending-import must not override a live supported chat tab

feat: clipboard-paste import + History fix, gist copy/share links, i1…

…8n override fix; bump to 0.4.27.0