Drawn icons throughout; file state and type as icons, no PENDING

- Every button's icon is drawn from one small SVG set (ICON), in bold
  strokes of the button's own colour, instead of font characters: ⟳ ⤓ ↗
  and the like came out thin and tiny and differed from font to font.
  Static buttons name theirs with data-icon. Keep is a flag everywhere.
- A file's state is an icon: a check when downloaded, a warning with the
  error in its tooltip when it failed, nothing while it waits. Its type
  (audio, video, image, pdf, torrent, other) is an icon with the word in
  its tooltip. The DOWNLOADED and PENDING chips are gone, which also
  fixes them being hard to read on Classic's blue selection.
- Tests find state and type by their tooltips.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016HdTEWQNrzyFULijigkmMn

CHANGELOG.md

@@ -34,7 +34,12 @@ The long form, with what was wrong before and how it was found, is in
 - Buttons are icons, with the words in their tooltips: the Files pane (save, delete, view,
   download), an item's own buttons (mark read, keep, open the original), the feed header (scan,
   download latest, mark all read, settings, unsubscribe), and the Settings, feed settings and
-  Download latest dialogs (save, download, cancel).
+  Download latest dialogs (save, download, cancel). The icons are drawn, from one set, rather
+  than font characters: ⟳ ⤓ ↗ and the like came out thin and tiny and differed from font to
+  font. Keep is a flag everywhere, as it was in the original.
+- A file's state and type are icons: a check when it is downloaded, a warning when it failed
+  (the error is in the tooltip), and nothing while it waits; audio, video, image, PDF, torrent
+  and other files each have their own. The DOWNLOADED and PENDING labels are gone.
 
 ### Security