feat(i18n): add app-wide localization framework and translator guide

- Add namespace-based JSON locale structure (en/es)
- Add I18n provider/context with locale persistence and fallback logic
- Add i18n parity checker script (npm run i18n:check)
- Wire app root/title shell to translation API
- Add TRANSLATION_GUIDE.md for contributors

TRANSLATION_GUIDE.md

@@ -0,0 +1,64 @@
+# Translation Guide
+
+This project uses a namespace-based i18n setup so contributors can localize safely without changing app logic.
+
+## Locale Files
+
+All locale files live under:
+
+- `src/i18n/locales/en/`
+- `src/i18n/locales/es/`
+
+Each locale has the same namespace files:
+
+- `common.json`
+- `launch.json`
+- `editor.json`
+- `timeline.json`
+- `settings.json`
+- `dialogs.json`
+- `shortcuts.json`
+
+English (`en`) is the source of truth for key structure.
+
+## Key Rules
+
+- Keep the same key paths across locales.
+- Do not rename existing keys unless coordinated with code changes.
+- Add new keys to `en` first, then mirror into all other locales.
+- Prefer descriptive, stable keys. Example: `app.editorTitle`.
+- Interpolation is supported with `{{name}}` style placeholders.
+
+## How Translation Is Read
+
+- Keys with a namespace prefix like `settings.export.title` use that namespace.
+- Keys without a namespace default to `common`.
+- Missing translations fall back to English, then to the provided fallback string, then to the key.
+
+## Validate Locale Structure
+
+Run:
+
+```bash
+npm run i18n:check
+```
+
+This checks for:
+
+- Missing namespace files
+- Missing keys compared to `en`
+- Extra keys not present in `en`
+
+## Contributor Workflow
+
+1. Pull latest `main`.
+2. Update `en/<namespace>.json` with new keys if needed.
+3. Add matching keys to other locale files.
+4. Run `npm run i18n:check`.
+5. Run app locally (`npm run dev`) and spot-check UI text.
+6. Open PR with a short summary of changed namespaces.
+
+## Scope Notes
+
+Current framework is app-wide and ready for full localization rollout.
+Not every UI string is migrated yet. Migration should be done incrementally by namespace to keep PRs reviewable and low-risk.

package.json

@@ -27,6 +27,7 @@
 		"build:mac": "npm run build:native-helpers && tsc && vite build && electron-builder --mac",
 		"build:win": "tsc && vite build && electron-builder --win",
 		"build:linux": "tsc && vite build && electron-builder --linux",
+		"i18n:check": "node scripts/i18n-check.mjs",
 		"test": "vitest --run",
 		"test:watch": "vitest"
 	},

scripts/i18n-check.mjs

@@ -0,0 +1,86 @@
+import fs from 'node:fs'
+import path from 'node:path'
+
+const root = process.cwd()
+const localesDir = path.join(root, 'src', 'i18n', 'locales')
+
+const locales = fs.readdirSync(localesDir).filter((entry) => {
+  const fullPath = path.join(localesDir, entry)
+  return fs.statSync(fullPath).isDirectory()
+})
+
+if (!locales.includes('en')) {
+  console.error('i18n-check: expected base locale directory "en"')
+  process.exit(1)
+}
+
+function loadJson(filePath) {
+  return JSON.parse(fs.readFileSync(filePath, 'utf8'))
+}
+
+function collectKeyPaths(obj, prefix = '') {
+  if (!obj || typeof obj !== 'object' || Array.isArray(obj)) {
+    return prefix ? [prefix] : []
+  }
+
+  const keys = Object.keys(obj)
+  if (keys.length === 0) {
+    return prefix ? [prefix] : []
+  }
+
+  const paths = []
+  for (const key of keys) {
+    const nextPrefix = prefix ? `${prefix}.${key}` : key
+    const value = obj[key]
+    if (value && typeof value === 'object' && !Array.isArray(value)) {
+      paths.push(...collectKeyPaths(value, nextPrefix))
+    } else {
+      paths.push(nextPrefix)
+    }
+  }
+  return paths
+}
+
+const baseLocaleDir = path.join(localesDir, 'en')
+const namespaceFiles = fs.readdirSync(baseLocaleDir).filter((file) => file.endsWith('.json'))
+
+let hasErrors = false
+
+for (const namespaceFile of namespaceFiles) {
+  const baseData = loadJson(path.join(baseLocaleDir, namespaceFile))
+  const baseKeys = new Set(collectKeyPaths(baseData))
+
+  for (const locale of locales) {
+    if (locale === 'en') continue
+
+    const localeFile = path.join(localesDir, locale, namespaceFile)
+    if (!fs.existsSync(localeFile)) {
+      console.error(`i18n-check: missing namespace file ${locale}/${namespaceFile}`)
+      hasErrors = true
+      continue
+    }
+
+    const localeData = loadJson(localeFile)
+    const localeKeys = new Set(collectKeyPaths(localeData))
+
+    for (const key of baseKeys) {
+      if (!localeKeys.has(key)) {
+        console.error(`i18n-check: missing key ${locale}/${namespaceFile}:${key}`)
+        hasErrors = true
+      }
+    }
+
+    for (const key of localeKeys) {
+      if (!baseKeys.has(key)) {
+        console.error(`i18n-check: extra key ${locale}/${namespaceFile}:${key}`)
+        hasErrors = true
+      }
+    }
+  }
+}
+
+if (hasErrors) {
+  process.exit(1)
+}
+
+console.log('i18n-check: locale files are structurally consistent')

src/App.tsx

@@ -5,15 +5,16 @@ import VideoEditor from "./components/video-editor/VideoEditor";
 import { loadAllCustomFonts } from "./lib/customFonts";
 import { ShortcutsProvider } from "./contexts/ShortcutsContext";
 import { ShortcutsConfigDialog } from "./components/video-editor/ShortcutsConfigDialog";
+import { useI18n } from "./contexts/I18nContext";
 
 export default function App() {
   const [windowType, setWindowType] = useState('');
+  const { locale, t } = useI18n();
 
   useEffect(() => {
     const params = new URLSearchParams(window.location.search);
     const type = params.get('windowType') || '';
     setWindowType(type);
-    document.title = type === 'editor' ? 'Recordly Editor' : 'Recordly';
 
     if (type === 'hud-overlay' || type === 'source-selector') {
       document.body.style.background = 'transparent';
@@ -27,6 +28,12 @@ export default function App() {
     });
   }, []);
 
+  useEffect(() => {
+    document.title = windowType === 'editor'
+      ? t('app.editorTitle', 'Recordly Editor')
+      : t('app.name', 'Recordly');
+  }, [windowType, locale, t]);
+
   switch (windowType) {
     case 'hud-overlay':
       return <LaunchWindow />;
@@ -43,14 +50,14 @@ export default function App() {
       return (
         <div className="flex h-full w-full items-center justify-center bg-slate-950 text-white">
           <div className="flex items-center gap-4 rounded-2xl border border-white/10 bg-white/5 px-6 py-5 shadow-2xl shadow-black/30 backdrop-blur-xl">
-            <img src="/app-icons/recordly-128.png" alt="Recordly" className="h-12 w-12 rounded-xl" />
+              <img src="/app-icons/recordly-128.png" alt={t('app.name', 'Recordly')} className="h-12 w-12 rounded-xl" />
             <div>
-              <h1 className="text-xl font-semibold tracking-tight">Recordly</h1>
-              <p className="text-sm text-white/65">Screen recording and editing</p>
+                <h1 className="text-xl font-semibold tracking-tight">{t('app.name', 'Recordly')}</h1>
+                <p className="text-sm text-white/65">{t('app.subtitle', 'Screen recording and editing')}</p>
             </div>
           </div>
         </div>
       );
   }
 }
-
+

src/contexts/I18nContext.tsx

@@ -0,0 +1,179 @@
+import {
+  createContext,
+  useCallback,
+  useContext,
+  useEffect,
+  useMemo,
+  useState,
+  type ReactNode,
+} from 'react'
+import {
+  DEFAULT_LOCALE,
+  I18N_NAMESPACES,
+  SUPPORTED_LOCALES,
+  type AppLocale,
+  type I18nNamespace,
+} from '@/i18n/config'
+import enCommon from '@/i18n/locales/en/common.json'
+import enDialogs from '@/i18n/locales/en/dialogs.json'
+import enEditor from '@/i18n/locales/en/editor.json'
+import enLaunch from '@/i18n/locales/en/launch.json'
+import enSettings from '@/i18n/locales/en/settings.json'
+import enShortcuts from '@/i18n/locales/en/shortcuts.json'
+import enTimeline from '@/i18n/locales/en/timeline.json'
+import esCommon from '@/i18n/locales/es/common.json'
+import esDialogs from '@/i18n/locales/es/dialogs.json'
+import esEditor from '@/i18n/locales/es/editor.json'
+import esLaunch from '@/i18n/locales/es/launch.json'
+import esSettings from '@/i18n/locales/es/settings.json'
+import esShortcuts from '@/i18n/locales/es/shortcuts.json'
+import esTimeline from '@/i18n/locales/es/timeline.json'
+
+const LOCALE_STORAGE_KEY = 'recordly.locale'
+
+type LocaleBundle = Record<I18nNamespace, Record<string, unknown>>
+
+const messages: Record<AppLocale, LocaleBundle> = {
+  en: {
+    common: enCommon,
+    launch: enLaunch,
+    editor: enEditor,
+    timeline: enTimeline,
+    settings: enSettings,
+    dialogs: enDialogs,
+    shortcuts: enShortcuts,
+  },
+  es: {
+    common: esCommon,
+    launch: esLaunch,
+    editor: esEditor,
+    timeline: esTimeline,
+    settings: esSettings,
+    dialogs: esDialogs,
+    shortcuts: esShortcuts,
+  },
+} as const
+
+interface I18nContextValue {
+  locale: AppLocale
+  setLocale: (locale: AppLocale) => void
+  t: (key: string, fallback?: string, vars?: Record<string, string | number>) => string
+}
+
+const I18nContext = createContext<I18nContextValue | null>(null)
+
+function isSupportedLocale(locale: string): locale is AppLocale {
+  return SUPPORTED_LOCALES.includes(locale as AppLocale)
+}
+
+function normalizeLocale(locale: string | null | undefined): AppLocale {
+  if (!locale) {
+    return DEFAULT_LOCALE
+  }
+
+  const normalized = locale.toLowerCase().split('-')[0]
+  return isSupportedLocale(normalized) ? normalized : DEFAULT_LOCALE
+}
+
+function getInitialLocale(): AppLocale {
+  if (typeof window === 'undefined') {
+    return DEFAULT_LOCALE
+  }
+
+  const storedLocale = window.localStorage.getItem(LOCALE_STORAGE_KEY)
+  if (storedLocale && isSupportedLocale(storedLocale)) {
+    return storedLocale
+  }
+
+  return normalizeLocale(window.navigator.language)
+}
+
+function getMessageValue(source: unknown, key: string): string | undefined {
+  const parts = key.split('.')
+  let current: unknown = source
+
+  for (const part of parts) {
+    if (!current || typeof current !== 'object' || !(part in current)) {
+      return undefined
+    }
+
+    current = (current as Record<string, unknown>)[part]
+  }
+
+  return typeof current === 'string' ? current : undefined
+}
+
+function interpolate(template: string, vars?: Record<string, string | number>) {
+  if (!vars) return template
+  return template.replace(/\{\{\s*([a-zA-Z0-9_]+)\s*\}\}/g, (_match, key) => {
+    const value = vars[key]
+    return value === undefined ? '' : String(value)
+  })
+}
+
+function parseKey(key: string): { namespace: I18nNamespace; path: string } {
+  const [first, ...rest] = key.split('.')
+  if (I18N_NAMESPACES.includes(first as I18nNamespace) && rest.length > 0) {
+    return { namespace: first as I18nNamespace, path: rest.join('.') }
+  }
+  return { namespace: 'common', path: key }
+}
+
+function translateForLocale(
+  locale: AppLocale,
+  key: string,
+  fallback?: string,
+  vars?: Record<string, string | number>,
+) {
+  const { namespace, path } = parseKey(key)
+
+  const rawValue =
+    getMessageValue(messages[locale][namespace], path)
+    ?? getMessageValue(messages[DEFAULT_LOCALE][namespace], path)
+    ?? fallback
+    ?? key
+
+  return interpolate(rawValue, vars)
+}
+
+export function I18nProvider({ children }: { children: ReactNode }) {
+  const [locale, setLocaleState] = useState<AppLocale>(getInitialLocale)
+
+  const setLocale = useCallback((nextLocale: AppLocale) => {
+    setLocaleState(nextLocale)
+    if (typeof window !== 'undefined') {
+      window.localStorage.setItem(LOCALE_STORAGE_KEY, nextLocale)
+    }
+  }, [])
+
+  useEffect(() => {
+    document.documentElement.lang = locale
+  }, [locale])
+
+  const t = useCallback((key: string, fallback?: string, vars?: Record<string, string | number>) => {
+    return translateForLocale(locale, key, fallback, vars)
+  }, [locale])
+
+  const value = useMemo<I18nContextValue>(() => ({
+    locale,
+    setLocale,
+    t,
+  }), [locale, setLocale, t])
+
+  return <I18nContext.Provider value={value}>{children}</I18nContext.Provider>
+}
+
+export function useI18n() {
+  const context = useContext(I18nContext)
+  if (!context) {
+    throw new Error('useI18n must be used within <I18nProvider>')
+  }
+  return context
+}
+
+export function useScopedT(namespace: I18nNamespace) {
+  const { t } = useI18n()
+  return useCallback((key: string, fallback?: string, vars?: Record<string, string | number>) => {
+    return t(`${namespace}.${key}`, fallback, vars)
+  }, [namespace, t])
+}

src/i18n/config.ts

@@ -0,0 +1,16 @@
+export const DEFAULT_LOCALE = 'en' as const
+
+export const SUPPORTED_LOCALES = ['en', 'es'] as const
+
+export const I18N_NAMESPACES = [
+  'common',
+  'launch',
+  'editor',
+  'timeline',
+  'settings',
+  'dialogs',
+  'shortcuts',
+] as const
+
+export type AppLocale = (typeof SUPPORTED_LOCALES)[number]
+export type I18nNamespace = (typeof I18N_NAMESPACES)[number]

src/i18n/locales/en/common.json

@@ -0,0 +1,7 @@
+{
+  "app": {
+    "name": "Recordly",
+    "editorTitle": "Recordly Editor",
+    "subtitle": "Screen recording and editing"
+  }
+}

src/i18n/locales/en/dialogs.json

@@ -0,0 +1 @@
+{}

src/i18n/locales/en/editor.json

@@ -0,0 +1 @@
+{}

src/i18n/locales/en/launch.json

@@ -0,0 +1 @@
+{}

src/i18n/locales/en/settings.json

@@ -0,0 +1 @@
+{}

src/i18n/locales/en/shortcuts.json

@@ -0,0 +1 @@
+{}

src/i18n/locales/en/timeline.json

@@ -0,0 +1 @@
+{}

src/i18n/locales/es/common.json

@@ -0,0 +1,7 @@
+{
+  "app": {
+    "name": "Recordly",
+    "editorTitle": "Editor de Recordly",
+    "subtitle": "Grabacion de pantalla y edicion"
+  }
+}

src/i18n/locales/es/dialogs.json

@@ -0,0 +1 @@
+{}

src/i18n/locales/es/editor.json

@@ -0,0 +1 @@
+{}

src/i18n/locales/es/launch.json

@@ -0,0 +1 @@
+{}

src/i18n/locales/es/settings.json

@@ -0,0 +1 @@
+{}

src/i18n/locales/es/shortcuts.json

@@ -0,0 +1 @@
+{}

src/i18n/locales/es/timeline.json

@@ -0,0 +1 @@
+{}

src/main.tsx

@@ -1,13 +1,16 @@
 import React from 'react'
 import ReactDOM from 'react-dom/client'
 import App from './App.tsx'
+import { I18nProvider } from './contexts/I18nContext.tsx'
 import './index.css'
 
 document.documentElement.dataset.platform = /mac/i.test(navigator.platform) ? 'macos' : 'other'
 
 ReactDOM.createRoot(document.getElementById('root')!).render(
   <React.StrictMode>
-    <App />
+    <I18nProvider>
+      <App />
+    </I18nProvider>
   </React.StrictMode>,
 )
-
+