feat: Migrate Arbiter and Modpack Version Checker to monorepo

WHAT WAS DONE:
- Migrated Arbiter (discord-oauth-arbiter) code to services/arbiter/
- Migrated Modpack Version Checker code to services/modpack-version-checker/
- Created .env.example for Arbiter with all required environment variables
- Moved systemd service file to services/arbiter/deploy/
- Organized directory structure per Gemini monorepo recommendations

WHY:
- Consolidate all service code in one repository
- Prepare for Gemini code review (Panel v1.12 compatibility check)
- Enable service-prefixed Git tagging (arbiter-v2.1.0, modpack-v1.0.0)
- Support npm workspaces for shared dependencies

SERVICES MIGRATED:
1. Arbiter (Discord OAuth bot) - Originally written by Gemini + Claude
   - Full source code from ops-manual docs/implementation/
   - Created comprehensive .env.example
   - Ready for Panel v1.12 compatibility verification

2. Modpack Version Checker (Python CLI tool)
   - Full source code from ops-manual docs/tasks/
   - Written for Panel v1.11, needs Gemini review for v1.12
   - Never had code review before

STILL TODO:
- Whitelist Manager - Pull from Billing VPS (38.68.14.188)
  - Currently deployed and running
  - Needs Panel v1.12 API compatibility fix (Task #86)
  - Requires SSH access to pull code

NEXT STEPS:
- Gemini code review for Panel v1.12 API compatibility
- Create package.json for each service
- Test npm workspaces integration
- Deploy after verification

FILES:
- services/arbiter/ (25 new files, full application)
- services/modpack-version-checker/ (21 new files, full application)

Signed-off-by: The Golden Chronicler <claude@firefrostgaming.com>

services/arbiter/.env.example

@@ -0,0 +1,34 @@
+# Arbiter Discord Bot - Environment Variables
+# Copy this file to .env and fill in actual values
+
+# Discord Bot Configuration
+DISCORD_BOT_TOKEN=your_discord_bot_token_here
+DISCORD_CLIENT_ID=your_discord_client_id_here
+DISCORD_CLIENT_SECRET=your_discord_client_secret_here
+GUILD_ID=your_discord_server_id_here
+
+# Application Configuration
+APP_URL=https://discord-bot.firefrostgaming.com
+PORT=3000
+NODE_ENV=production
+
+# Admin Access (comma-separated Discord user IDs)
+ADMIN_DISCORD_IDS=discord_id_1,discord_id_2,discord_id_3
+
+# Ghost CMS Integration
+CMS_URL=https://firefrostgaming.com
+CMS_ADMIN_KEY=your_ghost_admin_api_key_here
+
+# Paymenter Webhook Security
+WEBHOOK_SECRET=your_paymenter_webhook_secret_here
+
+# Session Security
+SESSION_SECRET=generate_random_32_char_string_here
+
+# Email Configuration (SMTP)
+SMTP_HOST=smtp.example.com
+SMTP_USER=your_email@firefrostgaming.com
+SMTP_PASS=your_email_password_here
+
+# Database (if applicable - check code)
+# DATABASE_URL=postgresql://user:pass@host:port/dbname