refactor: Externalize host configuration to hosts.json

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

hosts.json.example

@@ -0,0 +1,11 @@
+{
+    "http": [
+        "tanner.vc",
+        "forum.protospace.ca",
+        "protospace.ca",
+        "my.protospace.ca"
+    ],
+    "mqtt": [
+        "webhost.protospace.ca"
+    ]
+}

main.py

@@ -8,20 +8,16 @@ import asyncio
 import aiohttp
 import aiomqtt
 import ssl
+import json
 from datetime import datetime, timedelta
 
 
-HOSTS = {
-    'http': [
-        'tanner.vc',
-        'forum.protospace.ca',
-        'protospace.ca',
-        'my.protospace.ca',
-    ],
-    'mqtt': [
-        'webhost.protospace.ca',
-    ],
-}
+try:
+    with open('hosts.json', 'r') as f:
+        HOSTS = json.load(f)
+except FileNotFoundError:
+    logging.error("hosts.json not found. Please copy hosts.json.example to hosts.json and configure it.")
+    exit(1)
 
 
 def alert_tanner(msg):