test(ci): isolate CCS-managed env vars from host session

When tests run inside a CCS-managed Claude session, host env vars
(CLAUDE_CONFIG_DIR, CCS_PROFILE_TYPE) leak into subprocess spawns
and fixture setup, causing 9 test failures:

- persist-command-handler: reads real symlinked settings.json instead
  of temp fixture because CLAUDE_CONFIG_DIR overrides scoped CCS_HOME
- websearch-transformer: hook silently exits via shouldSkipHook()
  because CCS_PROFILE_TYPE=account triggers native_account_profile skip
- claudecode-env-stripping: normalizeSharedPluginMetadataPaths receives
  leaked CLAUDE_CONFIG_DIR instead of undefined for default profiles

Fix: clear CCS-managed env vars in beforeEach and neutralize
CCS_PROFILE_TYPE in subprocess env blocks.

Built [OnSteroids](https://onsteroids.ai)

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

@@ -101,6 +101,7 @@ function runHookWithMockedFetch(mode: 'success' | 'empty' | 'non-result' | 'fail
       }),
       env: {
         ...process.env,
+        CCS_PROFILE_TYPE: '',
         CCS_WEBSEARCH_ENABLED: '1',
         CCS_WEBSEARCH_SKIP: '0',
         CCS_WEBSEARCH_BRAVE: '0',
@@ -352,6 +353,7 @@ describe('websearch-transformer hook helpers', () => {
         }),
         env: {
           ...process.env,
+          CCS_PROFILE_TYPE: '',
           CCS_HOME: ccsHome,
           CCS_WEBSEARCH_TRACE: '1',
           CCS_WEBSEARCH_TRACE_LAUNCH_ID: 'hook-trace-test',
@@ -428,6 +430,7 @@ describe('websearch-transformer hook helpers', () => {
         }),
         env: {
           ...process.env,
+          CCS_PROFILE_TYPE: '',
           CCS_HOME: ccsHome,
           CCS_WEBSEARCH_TRACE: '1',
           CCS_WEBSEARCH_TRACE_FILE: disallowedTracePath,
@@ -509,6 +512,7 @@ global.fetch = async (url) => {
         }),
         env: {
           ...process.env,
+          CCS_PROFILE_TYPE: '',
           CCS_HOME: ccsHome,
           CCS_WEBSEARCH_TRACE: '1',
           CCS_WEBSEARCH_TRACE_LAUNCH_ID: 'quota-fallback-test',
@@ -623,6 +627,7 @@ global.fetch = async (url) => {
         }),
         env: {
           ...process.env,
+          CCS_PROFILE_TYPE: '',
           CCS_HOME: ccsHome,
           CCS_WEBSEARCH_TRACE: '1',
           CCS_WEBSEARCH_TRACE_LAUNCH_ID: 'cooldown-skip-test',
@@ -723,6 +728,7 @@ global.fetch = async (url) => {
         }),
         env: {
           ...process.env,
+          CCS_PROFILE_TYPE: '',
           CCS_HOME: ccsHome,
           CCS_WEBSEARCH_TRACE: '1',
           CCS_WEBSEARCH_TRACE_LAUNCH_ID: 'transient-retry-test',