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>

docs/platform-notes.md

@@ -17,7 +17,11 @@ Every platform seam carries a `PORTABILITY:` comment at the branch site.
 | Drive roots | `fs/local.ts listLocalDrives` | empty | `fsutil fsinfo drives` | empty |
 | chmod/Permissions | context-menu.service.ts, file-panel, file-actions | full | hidden for LOCAL panels (only flips read-only); SFTP unaffected | full |
 | Shell wording | `ui context-menu.service.ts` | Reveal in Finder / Move to Trash | Show in Explorer / Move to Recycle Bin | Show in File Manager |
-| Shortcut labels | `ui platform.ts MOD_LABEL/ALT_LABEL` | ⌘ / ⌥ | Ctrl+ / Alt+ | Ctrl+ / Alt+ |
+| Shortcut labels | `src/shared/keymap.ts formatCombo` (+ `keys.names.*`) | ⌘⇧⌥⌃ glyphs: ⇧⌘N | Ctrl+Shift+N, localized key names (Strg+Entf) | as Windows |
+| Command modifier | `keymap.ts` `Mod` | ⌘ only (⌃ stays Cocoa's text keys) | Ctrl | Ctrl |
+| Key equivalents | `shortcuts.service.ts claim` | page first, unclaimed → app menu | page only (no app menu) | page only |
+| Tab focus | `core/focus-cycle.ts cycleFocus` | WKWebView skips buttons/checkboxes without Keyboard navigation → walked by hand | native order (same walk) | native order (same walk) |
+| Reload keys | `platform.ts blockReloadKeys` | — | WebView2 reloads on F5 / Ctrl+R → swallowed when unclaimed | — |
 | Tray | `src/bun/tray.ts` | 22 pt template PNG | 16 px colored PNG | colored (needs AppIndicator, see below) |
 | App menu | `src/bun/menu.ts` | full menu incl. About | none (early return) — Settings opens from the tab-bar gear (Ctrl+,), About from its About section | none (unsupported upstream) |
 | connections.json protection | `store/connections.ts` | chmod 0600 | `icacls` current-user ACL (0600 is meaningless) | 0600 |