Drive the connection manager from the keyboard

The manager had only Esc and the scale keys: its list took one Tab stop
per row with no arrows, a stack's rename / delete / open-in-tabs buttons
existed only on hover, and no action had a key.

- Commands (the manager keymap scope, remappable like the rest): new
  connection with focus in Name, new stack, save, connect — or open the
  focused stack in tabs — delete the focused row, rename the focused
  stack, import from WinSCP, close the window.
- The list: up/down/Home/End move focus between rows (focus only:
  loading a connection would discard a half-edited form), Enter opens the
  focused connection, left/right collapse and expand a stack, and a
  stack's actions show while the keyboard is in its row.
- Enter in a form field connects; Esc leaves a field before it closes the
  window; Tab is walked by hand (WKWebView skips buttons and radios); focus
  comes back after a dialog and never stays lost on <body>.
- Tooltips show the keys; the Settings → Keyboard fixed-key list gains the
  manager's.

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

src/shared/i18n/es.ts

@@ -395,6 +395,7 @@ export const es = {
 			filter: "Teclear en la lista de archivos la filtra; {backspace} borra el último carácter del filtro",
 			shift: "Mayús con una tecla de movimiento selecciona las filas por las que pasa el cursor",
 			find: "{enter} y {shiftEnter} recorren las coincidencias de la búsqueda",
+			manager: "↑ ↓ ← → y {enter} recorren la lista de conexiones",
 			sidebar: "↑ ↓ cambian de sección aquí",
 		},
 		names: {