chore: harden runtime checks and split websocket inbound/outbound flows

scripts/run_test_ai_chat.ps1

@@ -0,0 +1,8 @@
+$ErrorActionPreference = "Stop"
+
+# Use a writable uv cache path on Windows to avoid permission issues
+# with default cache locations in restricted environments.
+$env:UV_CACHE_DIR = Join-Path $env:TEMP "uv-cache-tw-runtime"
+New-Item -ItemType Directory -Force $env:UV_CACHE_DIR | Out-Null
+
+uv run tests\test_ai_chat.py