fix: count the files selection and delete prompt with plurals

The files screen filled `files.selected_count` and
`files.delete_items_title` with its own `{name}` substitution, a
leftover from before t() took arguments, so they could not be
plurals. Both are ICU plurals now and every message on the screen gets
its values through t(). The upload progress line is one message
instead of "Uploading..." followed by the numbers.

locales/rn/en.json

@@ -415,7 +415,7 @@
   "files": {
     "delete_cascade_hint": "Folders are deleted along with everything inside them. This can't be undone.",
     "delete_item_title": "Delete this item?",
-    "delete_items_title": "Delete {count} items?",
+    "delete_items_title": "{count, plural, one {Delete # item?} other {Delete # items?}}",
     "done": "Done",
     "folder_empty": "This folder is empty",
     "invalid_name": "Invalid name",
@@ -424,7 +424,7 @@
     "open_error": "Could not open the file",
     "open_with": "Open with…",
     "preview_too_large": "This file is too large to preview.",
-    "selected_count": "{count} selected",
+    "selected_count": "{count, plural, one {# selected} other {# selected}}",
     "share_add_people": "Add people",
     "share_empty": "Not shared with anyone yet",
     "share_error": "Failed to update sharing",
@@ -438,7 +438,8 @@
     "share_unavailable": "Sharing is not available on this device",
     "shared_with": "Shared with",
     "sharing_access": "Sharing & access",
-    "upload_unavailable": "The file picker is not installed in this build. Rebuild the app to enable uploads."
+    "upload_unavailable": "The file picker is not installed in this build. Rebuild the app to enable uploads.",
+    "uploading_progress": "Uploading {current}/{total} · {name}"
   },
   "identities": {
     "badge": {

src/screens/FilesScreen.tsx

@@ -61,7 +61,7 @@ import {
   useSettingsStore, type FilesViewMode, type FilesSortKey, type FilesSortDir,
 } from '../stores/settings-store';
 import { useAuthStore } from '../stores/auth-store';
-import { useLocaleStore } from '../stores/locale-store';
+import { useLocaleStore, type TranslateFn } from '../stores/locale-store';
 import Dialog from '../components/Dialog';
 import ShareSheet from '../components/files/ShareSheet';
 import { FilePreviewModal, canPreviewInApp } from '../components/files/FilePreviewModal';
@@ -71,13 +71,7 @@ interface FileRow extends FileNode {
   displayName: string;
 }
 
-type Translate = (key: string, fallback?: string) => string;
-
-// The locale strings use `{name}`-style placeholders; the RN `t` does no
-// interpolation, so substitute here.
-function fill(text: string, vars: Record<string, string | number>): string {
-  return text.replace(/\{(\w+)\}/g, (_, k: string) => (k in vars ? String(vars[k]) : `{${k}}`));
-}
+type Translate = TranslateFn;
 
 const IMAGE_EXTS = ['png', 'jpg', 'jpeg', 'gif', 'webp', 'bmp'];
 
@@ -591,7 +585,7 @@ export default function FilesScreen() {
       if (maxSize > 0 && size != null && size > maxSize) {
         Alert.alert(
           t('files.upload_error', 'Failed to upload file'),
-          fill(t('files.file_too_large', '"{name}" exceeds the maximum file size ({max})'), {
+          t('files.file_too_large', '"{name}" exceeds the maximum file size ({max})', {
             name: asset.name,
             max: formatFileSize(maxSize),
           }),
@@ -683,7 +677,7 @@ export default function FilesScreen() {
               <X size={22} color={c.text} />
             </Pressable>
             <Text style={styles.title}>
-              {fill(t('files.selected_count', '{count} selected'), { count: selection.size })}
+              {t('files.selected_count', '{count, plural, one {# selected} other {# selected}}', { count: selection.size })}
             </Text>
             <View style={styles.headerActions}>
               <Pressable
@@ -812,7 +806,11 @@ export default function FilesScreen() {
           <View style={styles.progressRow}>
             <View style={{ flex: 1 }}>
               <Text style={styles.progressText} numberOfLines={1}>
-                {t('files.uploading', 'Uploading...')} {uploadProgress.current}/{uploadProgress.total} · {uploadProgress.name}
+                {t('files.uploading_progress', 'Uploading {current}/{total} · {name}', {
+                  current: uploadProgress.current,
+                  total: uploadProgress.total,
+                  name: uploadProgress.name,
+                })}
               </Text>
               <View style={styles.progressTrack}>
                 <View style={[styles.progressBar, { width: `${Math.round(uploadProgress.percent * 100)}%` }]} />
@@ -881,7 +879,7 @@ export default function FilesScreen() {
           <View style={styles.fileMetaRow}>
             {item.isShared && item.accountName ? (
               <Text style={styles.fileMeta} numberOfLines={1}>
-                {fill(t('files.shared_by', 'Shared by {name}'), { name: item.accountName })}
+                {t('files.shared_by', 'Shared by {name}', { name: item.accountName })}
               </Text>
             ) : null}
             {item.size != null && !isDir ? (
@@ -940,7 +938,7 @@ export default function FilesScreen() {
         </View>
         {item.isShared && item.accountName ? (
           <Text style={styles.gridMeta} numberOfLines={1}>
-            {fill(t('files.shared_by', 'Shared by {name}'), { name: item.accountName })}
+            {t('files.shared_by', 'Shared by {name}', { name: item.accountName })}
           </Text>
         ) : item.size != null && !isDir ? (
           <Text style={styles.gridMeta} numberOfLines={1}>
@@ -1120,7 +1118,7 @@ export default function FilesScreen() {
         visible={confirmDelete != null}
         title={
           confirmDelete && confirmDelete.rows.length > 1
-            ? fill(t('files.delete_items_title', 'Delete {count} items?'), { count: confirmDelete.rows.length })
+            ? t('files.delete_items_title', '{count, plural, one {Delete # item?} other {Delete # items?}}', { count: confirmDelete.rows.length })
             : t('files.delete_item_title', 'Delete this item?')
         }
         message={t('files.delete_cascade_hint', "Folders are deleted along with everything inside them. This can't be undone.")}