Fix: move /api/iata-coords route after app initialization

Route was at line 16 before express app was created — caused
'Cannot access app before initialization' crash on startup.

server.js

@@ -12,11 +12,6 @@ const decoder = require('./decoder');
 const PAYLOAD_TYPES = decoder.PAYLOAD_TYPES;
 const { nodeNearRegion, IATA_COORDS } = require('./iata-coords');
 
-// IATA coordinates for client-side regional filtering
-app.get('/api/iata-coords', (req, res) => {
-  res.json({ coords: IATA_COORDS });
-});
-
 // Health thresholds — configurable with sensible defaults
 const _ht = config.healthThresholds || {};
 const HEALTH = {
@@ -2919,6 +2914,11 @@ app.get('/api/analytics/subpath-detail', (req, res) => {
   res.json(_sdResult);
 });
 
+// IATA coordinates for client-side regional filtering
+app.get('/api/iata-coords', (req, res) => {
+  res.json({ coords: IATA_COORDS });
+});
+
 // Audio Lab: representative packets bucketed by type
 app.get('/api/audio-lab/buckets', (req, res) => {
   const buckets = {};