docs: add Bybit, OKX, and Lighter exchange support

- Mark Bybit, OKX as supported in CEX section
- Mark Lighter as supported in Perp-DEX section
- Add Bybit API setup guide
- Add OKX API setup guide
- Add Lighter agent wallet setup guide
- Update all READMEs (EN, ZH-CN, JA, KO)

docs/getting-started/bybit-api.md

@@ -0,0 +1,63 @@
+# Bybit API Setup Guide
+
+This guide explains how to create and configure Bybit API keys for use with NOFX.
+
+## Create API Key
+
+1. Log in to your [Bybit account](https://partner.bybit.com/b/83856)
+2. Go to **Account & Security** → **API Management**
+3. Click **Create New Key**
+4. Select **System-generated API Keys**
+5. Complete 2FA verification
+6. Name your API key (e.g., "NOFX Trading")
+
+## Configure API Permissions
+
+Enable the following permissions:
+
+- ✅ **Read-Write** - Required for trading
+- ✅ **Contract** - Required for futures/perpetual trading
+- ❌ **Withdrawals** - Keep disabled for security
+
+## IP Whitelist (Recommended)
+
+For enhanced security:
+
+1. Click **Edit** on your API key
+2. Add your server's IP address to the whitelist
+3. Save changes
+
+## Save Your Keys
+
+After creation, you'll see:
+- **API Key**: `xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx`
+- **API Secret**: `xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx`
+
+⚠️ **Important**: Save the API Secret immediately - it's only shown once!
+
+## Configure in NOFX
+
+Add your API credentials through the NOFX web interface:
+
+1. Open NOFX dashboard (http://localhost:3000)
+2. Go to **Exchange Configuration**
+3. Enable **Bybit**
+4. Enter your API Key and API Secret
+5. Save configuration
+
+## Troubleshooting
+
+| Error | Solution |
+|-------|----------|
+| `Invalid API key` | Check if API key is correct |
+| `Signature error` | Check if API Secret is correct |
+| `IP not allowed` | Add your IP to whitelist |
+| `Permission denied` | Enable Contract trading permission |
+
+## Security Best Practices
+
+- Never share your API keys
+- Use IP whitelisting
+- Don't enable withdrawal permissions
+- Create separate API keys for different applications
+- Regularly rotate your API keys