Create quick reference for DNS fix needed in next session

SCRATCH/dns_fix_reference.md

@@ -0,0 +1,48 @@
+# DNS Fix - provisionAgent.js
+
+## Quick Reference for Next Session
+
+**Status:** Identified but NOT yet applied  
+**Priority:** CRITICAL - blocks DNS record creation  
+**File:** `jester/zlh-api/src/api/provisionAgent.js`
+
+## The Problem
+EdgePublisher expects SHORT hostname but we're passing FQDN, breaking Cloudflare/Technitium DNS records.
+
+## The Fix (3 changes)
+
+### 1. Delete Line 46
+```javascript
+const ZONE = process.env.TECHNITIUM_ZONE || "zerolaghub.quest";
+```
+
+### 2. Delete Lines 330-331
+```javascript
+// Generate FQDN for DNS/EdgePublisher
+const slotHostname = `${hostname}.${ZONE}`;
+```
+
+### 3. Change Line 402
+```javascript
+// FROM:
+slotHostname,           // ← FQDN for DNS records
+
+// TO:
+slotHostname: hostname,  // ← SHORT hostname (EdgePublisher adds zone)
+```
+
+## Expected Result
+```javascript
+await enqueuePublishEdge({
+  vmid,
+  slotHostname: hostname,        // "mc-vanilla-5074"
+  instanceHostname: hostname,    // "mc-vanilla-5074" 
+  ports: allocatedPorts,
+  ctIp,
+  game: req.game,
+  txnId,
+});
+```
+
+## Why This Works
+Original working version (commit 9138add) passed short hostname. EdgePublisher adds zone suffix internally. Dev container refactor accidentally broke this by pre-appending FQDN.