Put every shortcut on one shared keymap and make the app keyboard-reachable

The keymap was scattered over ShortcutsService if-chains, the file panel's
key switch, macOS-only menu accelerators and hand-typed hints in 16
tooltips x 7 locales, and large parts of the app had no keyboard path at
all. src/shared/keymap.ts is now the one table: scopes, per-platform
defaults, exact matching, formatting with localized key names, conflicts,
reserved combos and native-menu accelerators, proven by keymap.spec.ts.

- ShortcutsService resolves against the effective keymap: claim() takes
  the key (preventDefault, held keys repeat only movement, never mid-IME),
  and from a text field only chords and F-keys fire. The file panel, App,
  editor, manager and Settings windows all dispatch through it.
- FileActionsService.run is the one file-command dispatcher for the list
  keys, the row menu, the macOS menu bar and the toolbar.
- New keys: the row menu (Shift+F10 / Menu / Ctrl+Return), the source
  picker (Mod+K), the path bar (Mod+L), transfers (Mod+J), sorting
  (Alt+1-7), Shift+movement selection, close other tabs, move and
  disconnect tabs, refresh and edit on Windows/Linux, permissions, copy
  path, reveal, trash, open in default app, editor find next/previous.
- Right-click menus: soft shortcut hints, icons on the everyday verbs
  (the toolbar's glyphs), section headers, scrolling, item keys while
  open, a highlighted first item when opened from the keyboard. The panel
  source picker now renders through the same menu.
- Dialogs: role=dialog, a Tab trap via cycleFocus (WKWebView skips
  buttons on Tab without Keyboard navigation), initial focus, Esc that
  stops propagating; the chmod dialog takes focus and applies on Enter.
- Fixed: Ctrl+Tab also flipped the active panel; Esc in a manager dialog
  closed the manager; Ctrl-F/T fired Cmd shortcuts on macOS; shortcuts
  fired under dialogs; keys died after any button click on macOS; the
  editor's save prompt and find box never got focus; WebView2 reload keys;
  a window could save default settings before its first load.
- Settings closes on its own close-window key (new settingsClose request).

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

src/bun/rpc-handlers.ts

@@ -467,6 +467,8 @@ export interface SettingsRpcHooks {
 	/** Every edit here is a settings save — rebroadcast it to the other windows. */
 	onSettingsSaved: (next: AppSettings) => void;
 	showAbout: () => void;
+	/** The window's own close-window key. */
+	close: () => void;
 }
 
 /** RPC for the single Settings window (per-window instance). */
@@ -483,6 +485,11 @@ export function createSettingsRPC(deps: { settings: SettingsStore }, hooks: Sett
 						hooks.showAbout();
 						return {};
 					}),
+				settingsClose: () =>
+					wrap(async () => {
+						hooks.close();
+						return {};
+					}),
 			},
 		},
 	});