feat(tools): add Claude Code skills for i18n and skill creation

Add custom Claude Code skills to support internationalization workflow and skill development.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: ericyangpan

.claude/skills/i18n/SKILL.md

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+---
+name: i18n
+description: Internationalization management tool for syncing and translating language files
+---
+
+# I18n Management Skill
+
+Manage multilingual content in the `messages/` directory. This skill provides tools to synchronize language files with the English reference and assist with translations.
+
+## Overview
+
+This project uses `next-intl` for internationalization with JSON message files stored in `messages/`:
+
+- `messages/en.json` - English (source of truth)
+- `messages/zh-Hans.json` - Simplified Chinese
+- Additional language files can be added
+
+All language files must maintain the same nested key structure as `en.json`.
+
+## Subcommands
+
+### `sync`
+
+Synchronize all language files with `en.json` as the source of truth.
+
+**What it does:**
+
+- Scans all `.json` files in `messages/` directory
+- Compares each file's keys with `en.json`
+- **Adds missing keys** with English text as placeholder (needs translation)
+- **Removes extra keys** not present in `en.json`
+- Preserves JSON structure and formatting (2-space indentation)
+
+**Usage:**
+
+When you need to sync language files, use this command in Claude Code:
+
+```
+Please run the i18n sync command
+```
+
+Claude Code will execute:
+
+```bash
+node .claude/skills/i18n/scripts/sync.mjs
+```
+
+**Output Example:**
+
+```
+🔄 Syncing language files with en.json...
+
+✓ Synced zh-Hans.json
+  + Added 3 keys
+  - Removed 1 key
+
+━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+✓ Sync complete!
+  Modified: 1 file
+  Added: 3 keys
+  Removed: 1 key
+```
+
+**When to use:**
+
+- After adding new keys to `en.json`
+- After removing obsolete keys from `en.json`
+- Before starting translation work (ensures all keys exist)
+- When adding a new language file
+
+---
+
+### `translate <locale>`
+
+Generate translation tasks for Claude Code to translate missing content.
+
+**What it does:**
+
+- Reads `en.json` and `<locale>.json`
+- Identifies keys that need translation (currently in English or missing)
+- Outputs a structured translation task with guidelines
+- Provides context and instructions for accurate translation
+
+**Usage:**
+
+When you need to translate content, use this command in Claude Code:
+
+```
+Please run the i18n translate command for zh-Hans
+```
+
+Claude Code will execute:
+
+```bash
+node .claude/skills/i18n/scripts/translate.mjs zh-Hans
+```
+
+**Workflow:**
+
+1. The script outputs content that needs translation in JSON format
+2. Claude Code reads the guidelines and translates the content
+3. You provide the translated JSON back
+4. Claude Code updates the language file
+
+**Translation Guidelines (automatically enforced):**
+
+✓ **Preserve brand names:** `AI Coding Stack`, `Claude Code`, etc.
+✓ **Keep placeholders intact:** `{count}`, `{name}`, `${variable}`
+✓ **Don't translate URLs:** `https://example.com`
+✓ **Don't translate file paths:** `/path/to/file`
+✓ **Maintain terminology consistency** throughout the translation
+
+**Supported Locales:**
+
+- `zh-Hans` - 简体中文 (Simplified Chinese)
+- `zh-Hant` - 繁體中文 (Traditional Chinese)
+- `ja` - 日本語 (Japanese)
+- `ko` - 한국어 (Korean)
+- `fr` - Français (French)
+- `de` - Deutsch (German)
+- `es` - Español (Spanish)
+- `pt` - Português (Portuguese)
+- `ru` - Русский (Russian)
+
+**Output Example:**
+
+```
+🌐 Translation Assistant for zh-Hans
+
+━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+📝 Translation Task
+━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+Target Language: 简体中文 (Simplified Chinese)
+Entries to translate: 15
+
+⚠ Translation Guidelines:
+  1. Preserve brand names: "AI Coding Stack", "Claude Code"
+  2. Keep placeholders intact: {count}, {name}, ${variable}
+  3. Don't translate URLs and file paths
+  4. Maintain consistent terminology
+
+Content to translate:
+
+{
+  "pages.home.title": "Welcome to AI Coding Stack",
+  "pages.home.description": "Discover the best AI coding tools",
+  ...
+}
+```
+
+---
+
+## File Structure
+
+```
+.claude/skills/i18n/
+├── SKILL.md              # This documentation
+└── scripts/
+    ├── sync.mjs          # Synchronization script
+    └── translate.mjs     # Translation assistant script
+```
+
+## Technical Details
+
+**Language:** Node.js (ES Modules)
+**Dependencies:** Built-in Node.js modules only (`fs`, `path`)
+**JSON Format:** 2-space indentation, trailing newline
+**Encoding:** UTF-8
+
+### How Keys Are Compared
+
+The scripts use recursive traversal to handle nested JSON structures. Keys are compared using dot notation:
+
+```json
+{
+  "pages": {
+    "home": {
+      "title": "Welcome"
+    }
+  }
+}
+```
+
+Becomes: `pages.home.title = "Welcome"`
+
+### Adding a New Language
+
+1. Add the locale to `src/i18n/config.ts`:
+
+```typescript
+export const locales = ['en', 'zh-Hans', 'ja'] as const; // Add 'ja'
+```
+
+2. Create an empty JSON file or copy `en.json`:
+
+```bash
+cp messages/en.json messages/ja.json
+```
+
+3. Run sync to ensure structure matches:
+
+```
+Please run the i18n sync command
+```
+
+4. Run translate to generate translation tasks:
+
+```
+Please run the i18n translate command for ja
+```
+
+## Best Practices
+
+1. **Always run `sync` before `translate`** to ensure all keys exist
+2. **Make changes to `en.json` first**, then sync other languages
+3. **Review translations** for context accuracy, especially technical terms
+4. **Use Git** to track changes and review diffs before committing
+5. **Keep brand names consistent** across all languages
+6. **Test translations** in the actual UI to verify formatting and length
+
+## Troubleshooting
+
+**Problem:** Script says "file not found"
+
+- **Solution:** Ensure you're running from project root
+- Check that `messages/` directory exists
+
+**Problem:** Keys are out of sync after adding new content
+
+- **Solution:** Run `sync` command to update all language files
+
+**Problem:** Translation contains placeholders like `{0}` instead of `{count}`
+
+- **Solution:** Verify the English source uses named placeholders, re-translate
+
+**Problem:** Some text appears in English in the translated app
+
+- **Solution:** Run `translate` to find missing translations, check for English fallbacks
+
+## Integration with next-intl
+
+This skill is designed to work with the project's `next-intl` setup:
+
+```typescript
+// src/i18n/request.ts
+export default getRequestConfig(async ({ locale }) => ({
+  messages: (await import(`../../messages/${locale}.json`)).default,
+}));
+```
+
+The JSON files are loaded dynamically based on the current locale.
+
+## License
+
+This skill is part of the AI Coding Stack project and follows the project's Apache 2.0 license.