feat(client): bump webssh2_client to 5.2.0 with Shift+Enter remap (#497)

Bundle integrity verified: provenance + checksums for v5.2.0.

Claude-Session: https://claude.ai/code/session_012jwDZSEKBhuQmhQuGujHC1

Author: billchurch

package-lock.json

@@ -48,7 +48,7 @@
     "socket.io": "^4.8.1",
     "ssh2": "1.17",
     "validator": "^13.15.35",
-    "webssh2_client": "5.1.0",
+    "webssh2_client": "5.2.0",
     "zod": "^4.1.12"
   },
   "scripts": {