test(websearch): clear CCS_PROFILE_TYPE in SearXNG fallback spawn env

The SearXNG-to-DuckDuckGo fallback test inherited the caller's CCS_PROFILE_TYPE
via `...process.env`, causing the hook to take the 'native_default_profile'
skip path and produce empty stdout. All other subprocess spawns in this file
set CCS_PROFILE_TYPE to NEUTRAL_PROFILE_TYPE; this one was the outlier.

Deterministic locally when CCS_PROFILE_TYPE=default is set in the shell.

tests/unit/hooks/websearch-transformer.test.ts

@@ -465,6 +465,7 @@ global.fetch = async (url) => {
         }),
         env: {
           ...process.env,
+          CCS_PROFILE_TYPE: NEUTRAL_PROFILE_TYPE,
           CCS_WEBSEARCH_ENABLED: '1',
           CCS_WEBSEARCH_SKIP: '0',
           CCS_WEBSEARCH_BRAVE: '0',