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/src/cmsService.js

@@ -0,0 +1,57 @@
+// src/cmsService.js
+// Ghost CMS Admin API integration for member management
+
+const api = require('@tryghost/admin-api');
+
+const cms = new api({
+    url: process.env.CMS_URL,
+    key: process.env.CMS_ADMIN_KEY,
+    version: 'v5.0'
+});
+
+/**
+ * Find a Ghost member by their email address
+ * @param {string} email - Email address to search for
+ * @returns {Promise<Object>} - Ghost member object
+ * @throws {Error} - If member not found
+ */
+async function findMemberByEmail(email) {
+    // We use the browse method with a filter to find the exact match
+    const members = await cms.members.browse({ filter: `email:'${email}'` });
+    
+    if (members.length === 0) {
+        throw new Error('Member not found');
+    }
+    
+    // Return the first match
+    return members[0]; 
+}
+
+/**
+ * Update a Ghost member's discord_id custom field
+ * @param {string} email - Member's email address
+ * @param {string} discordId - Discord user ID (snowflake)
+ * @returns {Promise<Object>} - Updated member object
+ */
+async function updateMemberDiscordId(email, discordId) {
+    const members = await cms.members.browse({ filter: `email:'${email}'` });
+    
+    if (members.length === 0) {
+        throw new Error('Member not found in CMS');
+    }
+
+    const updated = await cms.members.edit({
+        id: members[0].id,
+        custom_fields: [
+            { name: 'discord_id', value: discordId }
+        ]
+    });
+    
+    console.log(`[Ghost] Updated discord_id for ${email}`);
+    return updated;
+}
+
+module.exports = { 
+    findMemberByEmail, 
+    updateMemberDiscordId 
+};