fix(files): review round 2, the page — the viewer's Escape, the dialog's drop, the capped list's honesty

- Escape closes the file viewer again: its layer sits above its dialog's, so it takes the Escape.
- The page's drop guard leaves a drag the open Upload dialog's zone accepted alone (it ran last and
  refused that drop).
- A capped list's server sort or search keeps the rows on screen until its answer is in (no skeleton
  under the pressed header), says "The first N items" when that answer is cut too, and an arrival is
  decided on the rows shown: one past the end of a cut list is said to be so, not gone.
- The search an arrival clears is taken at once.
- Tests: confirm names asserted per confirm, a fitting text pages under the arrows, a deleted file
  leaves the tray's finished list.

frontend/src/i18n/locales/en/files.json

@@ -5,10 +5,13 @@
   "count_other": "{{count}} items",
   "countNewest_one": "The newest {{count}} item",
   "countNewest_other": "The newest {{count}} items",
+  "countFirst_one": "The first {{count}} item",
+  "countFirst_other": "The first {{count}} items",
   "rowMenu": "File actions",
   "folderUnknown": "This folder could not be loaded",
   "arrival": {
-    "gone": "That file is no longer in your library"
+    "gone": "That file is no longer in your library",
+    "notListed": "That file is past the end of this list — search for it by name"
   },
   "phoneOk": "Plays on a phone too",
   "rail": {

frontend/src/i18n/locales/hu/files.json

@@ -5,10 +5,13 @@
   "count_other": "{{count}} elem",
   "countNewest_one": "A legújabb {{count}} elem",
   "countNewest_other": "A legújabb {{count}} elem",
+  "countFirst_one": "Az első {{count}} elem",
+  "countFirst_other": "Az első {{count}} elem",
   "rowMenu": "Fájl műveletei",
   "folderUnknown": "Ez a mappa nem tölthető be",
   "arrival": {
-    "gone": "Ez a fájl már nincs a könyvtáradban"
+    "gone": "Ez a fájl már nincs a könyvtáradban",
+    "notListed": "Ez a fájl kimaradt a listából — keress rá a nevére"
   },
   "phoneOk": "Telefonon is lejátszható",
   "rail": {