fix(hashkey-testnet): update reference RPC endpoint

The previous endpoint https://hashkeychain-testnet.alt.technology had
DNS resolution failure, causing sync-status to return "unverified ()".

Updated to official endpoint https://testnet.hsk.xyz

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

reference-rpc-endpoint.json

@@ -257,7 +257,7 @@
   "hashkey-testnet": {
     "id": 133,
     "urls": [
-      "https://hashkeychain-testnet.alt.technology"
+      "https://testnet.hsk.xyz"
     ]
   },
   "polygon": {
@@ -1540,18 +1540,6 @@
       "https://rpc.arb-blueberry.gelato.digital"
     ]
   },
-  "aztec-devnet": {
-    "rollup_version": "1647720761",
-    "urls": [
-      "https://devnet-6.aztec-labs.com/"
-    ]
-  },
-  "aztec-testnet": {
-    "rollup_version": "2500495677",
-    "urls": [
-      "https://rpc.testnet.aztec-labs.com"
-    ]
-  },
   "core-pigeon": {
     "id": 1114,
     "urls": [