Desktop D2 UI: design system, portfolio, release timeline, catalog parity, listings, health, reviews, TestFlight, checks, command palette, toasts, first-run guide, en + tr with i18n check, 7:1 theme check, dev fixture mode and screenshot harness

apps/desktop/src/i18n/index.ts

@@ -0,0 +1,33 @@
+// UI strings: English and Turkish catalogs with the same keys (tr.ts is typed against en.ts; tools/i18n-check.ts also
+// checks empty strings and placeholder parity in CI). `t(key, vars)`: "{name}" placeholders; with a numeric `count`,
+// a "<key>_one" entry is used for 1 when the catalog has one.
+import { en } from './en';
+import { tr } from './tr';
+
+export type Key = keyof typeof en;
+export type Vars = Record<string, string | number>;
+export type UiLang = 'en' | 'tr';
+
+export const CATALOGS: Record<UiLang, Record<Key, string>> = { en, tr };
+let current: UiLang = 'en';
+
+export function setLang(l: UiLang): void { current = l; }
+export function lang(): UiLang { return current; }
+
+export function format(s: string, vars?: Vars): string {
+  if (!vars) return s;
+  return s.replace(/\{(\w+)\}/g, (m, k: string) => (vars[k] === undefined ? m : String(vars[k])));
+}
+
+export function t(key: Key, vars?: Vars): string {
+  const cat = CATALOGS[current];
+  let k: Key = key;
+  if (vars && vars.count === 1) {
+    const one = `${key}_one` as Key;
+    if (one in cat) k = one;
+  }
+  return format(cat[k] ?? en[k] ?? key, vars);
+}
+
+/** Placeholders of a message ("{count} apps" -> ["count"]), sorted, for the parity check. */
+export const placeholders = (s: string): string[] => [...s.matchAll(/\{(\w+)\}/g)].map(m => m[1]!).sort();