Changes:
- Disable telemetry by default (opt-in instead of opt-out)
- Strip user query text and LLM response text from telemetry events
- Remove server_identifiers and tools_available_names from telemetry
- Default search_scope to 'local' (no auto-import of unverified cloud skills)
- Default auto_import to False in search_skills
- Scope OpenClaw credential reading to openspace env block only
- Enable sandbox by default in security config
- Add SECURITY.md with guidance for users
See PR description for full security audit findings.
