One icon per meaning across the UI; mark everything read in All Subscriptions

- All Subscriptions' header checks every feed and marks everything read
  (POST /api/read-all, the same feeds the view lists); it asks first.
- Minus unsubscribes everywhere (the feed header's x read as "close"),
  x only closes or cancels, plus adds/subscribes/imports, and a dialog's
  confirm carries its action's icon. Remaining word buttons, the player
  and the folder arrow are Font Awesome 7.3.1 icons.
- Toolbar grouped by what it acts on (add, unsubscribe, scan | play,
  read, keep); read and keep show the selected item's state.
- The OPML subscription page uses the same header as a feed.
- Fixed: Escape ignored inside a dialog's text box (Add feed could not
  be closed with it), white password box in the dark theme, stray dot
  in an undated item's details.
- Tests: one action one icon across toolbar, page and all 8 dialogs;
  All Subscriptions mark everything read.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0173mGu6rK18Ne7UGTwAaVJV

docs/architecture.md

@@ -107,6 +107,7 @@ else a `401`.
 | `GET /api/feeds/{id}/entries` | paged, filtered, searchable |
 | `GET /api/entries` | the same, across every feed you subscribe to (All Subscriptions) |
 | `POST /api/feeds/{id}/read-all`, `POST /api/feeds/{id}/download-latest` | |
+| `POST /api/read-all` | everything read in every feed you subscribe to (All Subscriptions) |
 | `POST /api/entries/{feed}/{guid}/flags`, `…/position` | your read, starred, position |
 | `POST /api/enclosures/{id}/download`, `DELETE /api/enclosures/{id}` | `?force=true` overrides the shared-file warning |
 | `POST /api/fetch` | |