Add i18n foundation and translations (#1027)

* feat: add i18n foundation

* feat: localize sessions sidebar

* Localize multirun/scheduled tasks and fix dialog dropdown interactions

* localize git sidebar surface and add zh-CN keys

* feat(ui): localize context panel, diff/plan views, and context sidebar content

* fix(config): resolve user config home via fs/home before embedded home

* localize header/chat UI and complete model/worktree panel strings

* localize worktree + github issue/pr dialog flows

* localize settings sections and split settings i18n dictionaries

* localize additional settings sections and sidebars

* localize more settings pages and dialogs

* fix settings select trigger localization

* localize tunnel settings ui surface

* localize additional settings sections

* localize keyboard shortcuts labels in settings

* localize terminal and utility dialogs surfaces

* feat(i18n): localize remaining UI strings

* Add Ukrainian locale

* Add Spanish locale

* Add Brazilian Portuguese locale

* Polish locale translations

packages/ui/src/components/session/SaveProjectPlanDialog.tsx

@@ -9,6 +9,7 @@ import {
   DialogTitle,
 } from '@/components/ui/dialog';
 import { Input } from '@/components/ui/input';
+import { useI18n } from '@/lib/i18n';
 
 type SaveProjectPlanDialogProps = {
   open: boolean;
@@ -20,6 +21,7 @@ type SaveProjectPlanDialogProps = {
 };
 
 export function SaveProjectPlanDialog(props: SaveProjectPlanDialogProps) {
+  const { t } = useI18n();
   const { open, onOpenChange, initialTitle, sourceText, saving = false, onSave } = props;
   const [title, setTitle] = React.useState(initialTitle);
 
@@ -35,24 +37,24 @@ export function SaveProjectPlanDialog(props: SaveProjectPlanDialogProps) {
     <Dialog open={open} onOpenChange={(nextOpen) => { if (!saving) onOpenChange(nextOpen); }}>
       <DialogContent className="max-w-lg">
         <DialogHeader>
-          <DialogTitle>Save as plan</DialogTitle>
-          <DialogDescription>Choose a title for the saved markdown plan file.</DialogDescription>
+          <DialogTitle>{t('saveProjectPlanDialog.title')}</DialogTitle>
+          <DialogDescription>{t('saveProjectPlanDialog.description')}</DialogDescription>
         </DialogHeader>
 
         <div className="space-y-3">
           <div className="space-y-1.5">
-            <label className="typography-ui-label font-medium text-foreground">Title</label>
+            <label className="typography-ui-label font-medium text-foreground">{t('saveProjectPlanDialog.field.title')}</label>
             <Input
               value={title}
               onChange={(event) => setTitle(event.target.value)}
-              placeholder="Plan title"
+              placeholder={t('saveProjectPlanDialog.field.titlePlaceholder')}
               autoFocus
               disabled={saving}
             />
           </div>
 
           <div className="space-y-1.5">
-            <label className="typography-ui-label font-medium text-foreground">Content preview</label>
+            <label className="typography-ui-label font-medium text-foreground">{t('saveProjectPlanDialog.field.contentPreview')}</label>
             <div className="max-h-40 overflow-auto rounded-lg border border-border/70 bg-[var(--surface-subtle)] px-3 py-2 typography-meta text-foreground">
               {sourceText}
             </div>
@@ -60,9 +62,9 @@ export function SaveProjectPlanDialog(props: SaveProjectPlanDialogProps) {
         </div>
 
         <DialogFooter>
-          <Button variant="outline" onClick={() => onOpenChange(false)} disabled={saving}>Cancel</Button>
+          <Button variant="outline" onClick={() => onOpenChange(false)} disabled={saving}>{t('saveProjectPlanDialog.actions.cancel')}</Button>
           <Button onClick={() => void onSave(trimmedTitle)} disabled={!trimmedTitle || saving}>
-            {saving ? 'Saving...' : 'Save'}
+            {saving ? t('saveProjectPlanDialog.actions.saving') : t('saveProjectPlanDialog.actions.save')}
           </Button>
         </DialogFooter>
       </DialogContent>