docs: split WeCom configuration into Chinese and English versions

- Rename docs/wecom-app-configuration.md to -cn.md (Chinese)
- Create docs/wecom-app-configuration-en.md (English translation)

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Co-Authored-By: Z.ai GLM-5

docs/wecom-app-configuration-en.md

@@ -0,0 +1,117 @@
+# WeCom App Configuration Guide
+
+This document explains how to configure the WeCom App (wecom-app) channel in PicoClaw.
+
+## Features
+
+| Feature | Status |
+|---------|--------|
+| Receive messages | ✅ |
+| Send messages | ✅ |
+| Private chat | ✅ |
+| Group chat | ❌ |
+
+## Configuration Steps
+
+### 1. WeCom Admin Console Setup
+
+1. Log in to [WeCom Admin Console](https://work.weixin.qq.com/wework_admin)
+2. Go to "Application Management" → Select your custom app
+3. Record the following information:
+   - **AgentId**: Shown on the app details page
+   - **Secret**: Click "View" to get it
+4. Go to "My Company" page and record the **CorpID** (Enterprise ID)
+
+### 2. Message Reception Configuration
+
+1. On the app details page, click "Set API Receiver" under "Receive Messages"
+2. Fill in the following:
+   - **URL**: `http://your-server:18792/webhook/wecom-app`
+   - **Token**: Randomly generated or custom (for signature verification)
+   - **EncodingAESKey**: Click "Random Generate" to generate a 43-character key
+3. When you click "Save", WeCom will send a verification request
+
+### 3. PicoClaw Configuration
+
+Add the following configuration to your `config.json`:
+
+```json
+{
+  "channels": {
+    "wecom_app": {
+      "enabled": true,
+      "corp_id": "wwxxxxxxxxxxxxxxxx",           // Enterprise ID
+      "corp_secret": "xxxxxxxxxxxxxxxxxxxxxxxx", // App Secret
+      "agent_id": 1000002,                        // App AgentId
+      "token": "your_token",                      // Token from message reception config
+      "encoding_aes_key": "your_encoding_aes_key", // EncodingAESKey from message reception config
+      "webhook_host": "0.0.0.0",
+      "webhook_port": 18792,
+      "webhook_path": "/webhook/wecom-app",
+      "allow_from": [],
+      "reply_timeout": 5
+    }
+  }
+}
+```
+
+## Troubleshooting
+
+### 1. Callback URL Verification Failed
+
+**Symptom**: WeCom shows verification failed when saving API receiver settings
+
+**Check**:
+- Confirm server firewall has port 18792 open
+- Confirm `corp_id`, `token`, `encoding_aes_key` are configured correctly
+- Check PicoClaw logs for incoming requests
+
+### 2. Chinese Message Decryption Failed
+
+**Symptom**: `invalid padding size` error when sending Chinese messages
+
+**Cause**: WeCom uses non-standard PKCS7 padding (32-byte block size)
+
+**Solution**: Ensure you're using the latest version of PicoClaw, which has fixed this issue.
+
+### 3. Port Conflict
+
+**Symptom**: Port already in use error at startup
+
+**Solution**: Change `webhook_port` to another port, e.g., 18794
+
+## Technical Details
+
+### Encryption Algorithm
+
+- **Algorithm**: AES-256-CBC
+- **Key**: 32 bytes from Base64-decoded EncodingAESKey
+- **IV**: First 16 bytes of AESKey
+- **Padding**: PKCS7 (32-byte block size, not standard 16 bytes)
+- **Message Format**: XML
+
+### Message Structure
+
+Decrypted message format:
+```
+random(16B) + msg_len(4B) + msg + receiveid
+```
+
+Where `receiveid` is `corp_id` for custom apps.
+
+## Debugging
+
+Enable debug mode to see detailed logs:
+
+```bash
+picoclaw gateway --debug
+```
+
+Key log identifiers:
+- `wecom_app`: WeCom App channel related logs
+- `wecom_common`: Encryption/decryption related logs
+
+## References
+
+- [WeCom Official Documentation - Receiving Messages](https://developer.work.weixin.qq.com/document/path/96211)
+- [WeCom Official Encryption Library](https://github.com/sbzhu/weworkapi_golang)