Initial CodeCraft: web-based coding harness for AI models

Rust backend (axum/tokio): agent loop with streaming, tools (fs, bash,
web_fetch, todo, ask_user, subagents, skills, craft snapshots/compare),
permissions with modes and rules, Anthropic + OpenAI-compatible providers,
MCP client (stdio/HTTP, elicitation), SQLite sessions, usage statistics,
compaction, commented TOML config editable via toml_edit.

React PWA: chat with live streaming, permission/question cards, modes
(build/plan/craft), settings for providers/models/prices/MCP/permissions,
raw config editor, statistics dashboard, i18n (en/de). Docker setup.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/i18n/index.ts

@@ -0,0 +1,104 @@
+// Minimal i18n: dictionaries per language, `{name}` placeholders, persisted choice.
+// To add a language: copy en.ts, translate the values, register it in `languages`.
+// TypeScript enforces that every language defines every key of `en`.
+
+import { useSyncExternalStore } from "react";
+import { en, type Messages } from "./en";
+import { de } from "./de";
+
+export type Key = keyof typeof en;
+
+export const languages: Record<string, { name: string; messages: Messages }> = {
+  en: { name: "English", messages: en },
+  de: { name: "Deutsch", messages: de },
+};
+
+const STORAGE_KEY = "codecraft.lang";
+
+function detect(): string {
+  const saved = localStorage.getItem(STORAGE_KEY);
+  if (saved && languages[saved]) return saved;
+  const nav = navigator.language.slice(0, 2);
+  return languages[nav] ? nav : "en";
+}
+
+let current = detect();
+document.documentElement.lang = current;
+const listeners = new Set<() => void>();
+
+export function getLang() {
+  return current;
+}
+
+export function setLang(lang: string) {
+  if (!languages[lang]) return;
+  current = lang;
+  localStorage.setItem(STORAGE_KEY, lang);
+  document.documentElement.lang = lang;
+  listeners.forEach((l) => l());
+}
+
+export function t(key: Key, vars?: Record<string, string | number>): string {
+  let s: string = languages[current].messages[key] ?? en[key] ?? key;
+  if (vars) {
+    for (const [k, v] of Object.entries(vars)) s = s.replaceAll(`{${k}}`, String(v));
+  }
+  return s;
+}
+
+/** Re-render on language change. Returns `t` for convenience. */
+export function useT() {
+  useSyncExternalStore(
+    (l) => {
+      listeners.add(l);
+      return () => listeners.delete(l);
+    },
+    () => current,
+  );
+  return t;
+}
+
+// --- locale-aware formatting -------------------------------------------------
+
+export function fmtNumber(n: number, digits = 0) {
+  return new Intl.NumberFormat(current, { maximumFractionDigits: digits }).format(n);
+}
+
+export function fmtCompact(n: number) {
+  return new Intl.NumberFormat(current, { notation: "compact", maximumFractionDigits: 1 }).format(n);
+}
+
+export function fmtCost(n: number, currency: string) {
+  const digits = n !== 0 && Math.abs(n) < 1 ? 4 : 2;
+  try {
+    return new Intl.NumberFormat(current, { style: "currency", currency, maximumFractionDigits: digits }).format(n);
+  } catch {
+    return `${n.toFixed(digits)} ${currency}`;
+  }
+}
+
+export function fmtPercent(n: number) {
+  return new Intl.NumberFormat(current, { style: "percent", maximumFractionDigits: 1 }).format(n);
+}
+
+export function fmtDate(ms: number, withTime = true) {
+  return new Intl.DateTimeFormat(current, withTime ? { dateStyle: "medium", timeStyle: "short" } : { dateStyle: "medium" }).format(ms);
+}
+
+export function fmtRelative(ms: number) {
+  const diff = (ms - Date.now()) / 1000;
+  const rtf = new Intl.RelativeTimeFormat(current, { numeric: "auto" });
+  const abs = Math.abs(diff);
+  if (abs < 60) return rtf.format(Math.round(diff), "second");
+  if (abs < 3600) return rtf.format(Math.round(diff / 60), "minute");
+  if (abs < 86400) return rtf.format(Math.round(diff / 3600), "hour");
+  return rtf.format(Math.round(diff / 86400), "day");
+}
+
+export function weekdayNames(): string[] {
+  // Index 0 = Sunday, matching SQLite's %w.
+  const base = new Date(Date.UTC(2024, 0, 7)); // a Sunday
+  return Array.from({ length: 7 }, (_, i) =>
+    new Intl.DateTimeFormat(current, { weekday: "short", timeZone: "UTC" }).format(new Date(base.getTime() + i * 86400000)),
+  );
+}