Internationalization: 7 languages with live switching

Custom signal-based runtime (no i18n dependency): shared src/shared/i18n
dictionaries, ui I18nService.t() reactive by construction so language
switches live, and a backend i18n.ts for native menus + thrown errors.
Every user-facing string keyed across templates, toasts, dialogs, file
kinds, columns, macOS menu/context menus, and errors. Language picker in
Options (auto-detects OS locale, falls back to English); switching
relabels the webview and native chrome instantly. English/Spanish/French/
German fully drafted; Chinese/Japanese/Basque drafted, flagged for native
review. Docs updated.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

ui/src/app/file-actions.service.ts

@@ -6,6 +6,7 @@ import { type PanelState, type Side } from './panels.service';
 import { IS_WINDOWS } from './platform';
 import { RpcService } from './rpc.service';
 import { SettingsService } from './settings.service';
+import { I18nService } from './i18n.service';
 import { ToastService } from './toast.service';
 
 /** The row (or empty space) the user last right-clicked; ctx-* actions apply here. */
@@ -21,6 +22,7 @@ export interface MenuTarget {
  */
 @Injectable({ providedIn: 'root' })
 export class FileActionsService {
+  private readonly i18n = inject(I18nService);
   private readonly rpc = inject(RpcService);
   private readonly toast = inject(ToastService);
   private readonly dialogs = inject(DialogsService);
@@ -44,7 +46,7 @@ export class FileActionsService {
   async trash(panel: PanelState, entry: FileEntry): Promise<void> {
     const res = await this.rpc.request.moveToTrash({ path: entry.path });
     if (!res.ok) this.toast.error(res.error);
-    else this.toast.info(`Moved "${entry.name}" to Trash`);
+    else this.toast.info(this.i18n.t('toasts.movedToTrash', { name: entry.name }));
     await panel.refresh();
   }
 
@@ -58,9 +60,9 @@ export class FileActionsService {
 
   mkdir(panel: PanelState): void {
     this.dialogs.prompt.set({
-      title: 'New folder',
-      placeholder: 'folder name',
-      confirmLabel: 'Create',
+      title: this.i18n.t('fileActions.newFolderTitle'),
+      placeholder: this.i18n.t('fileActions.newFolderPlaceholder'),
+      confirmLabel: this.i18n.t('fileActions.createConfirm'),
       onConfirm: async (name) => {
         const res = await this.rpc.request.mkdir({
           sessionId: panel.sessionId(),
@@ -74,9 +76,9 @@ export class FileActionsService {
 
   createFile(panel: PanelState): void {
     this.dialogs.prompt.set({
-      title: 'New file',
-      placeholder: 'file name',
-      confirmLabel: 'Create',
+      title: this.i18n.t('fileActions.newFileTitle'),
+      placeholder: this.i18n.t('fileActions.newFilePlaceholder'),
+      confirmLabel: this.i18n.t('fileActions.createConfirm'),
       onConfirm: async (name) => {
         const res = await this.rpc.request.createFile({
           sessionId: panel.sessionId(),
@@ -101,7 +103,7 @@ export class FileActionsService {
       if (!res.ok) {
         this.toast.error(res.error);
       } else if (res.watching) {
-        this.toast.info(`Editing ${entry.name} — saves upload automatically`);
+        this.toast.info(this.i18n.t('toasts.editingExternal', { name: entry.name }));
       }
       return;
     }
@@ -120,9 +122,9 @@ export class FileActionsService {
     const entry = panel.sorted()[panel.cursor()];
     if (!entry || entry.name === '..') return;
     this.dialogs.prompt.set({
-      title: `Rename "${entry.name}"`,
+      title: this.i18n.t('fileActions.renameTitle', { name: entry.name }),
       initial: entry.name,
-      confirmLabel: 'Rename',
+      confirmLabel: this.i18n.t('fileActions.renameConfirm'),
       onConfirm: async (name) => {
         if (name === entry.name) return;
         const res = await this.rpc.request.rename({
@@ -140,11 +142,13 @@ export class FileActionsService {
     const targets = this.targets(panel);
     if (!targets.length) return;
     const what =
-      targets.length === 1 ? `"${targets[0].name}"` : `${targets.length} items`;
+      targets.length === 1
+        ? `"${targets[0].name}"`
+        : this.i18n.t('fileActions.itemsCount', { count: targets.length });
     this.dialogs.confirm.set({
-      title: 'Delete',
-      body: `Delete ${what}? Folders are deleted recursively. This cannot be undone.`,
-      confirmLabel: 'Delete',
+      title: this.i18n.t('fileActions.deleteTitle'),
+      body: this.i18n.t('fileActions.deleteBody', { what }),
+      confirmLabel: this.i18n.t('fileActions.deleteConfirm'),
       destructive: true,
       onConfirm: async () => {
         const res = await this.rpc.request.deleteEntries({