Replace 12 flat parameters (code_file, code_before, code_after, code_diff,
and 8 CVSS fields) with structured nested XML fields: code_locations with
co-located fix_before/fix_after per location, cvss_breakdown, and cwe.
This enables multi-file vulnerability locations, per-location fixes with
precise line numbers, data flow representation (source/sink), CWE
classification, and compatibility with GitHub/GitLab PR review APIs.
- Add dedupe.py with XML-based LLM deduplication using direct litellm calls
- Integrate deduplication check in create_vulnerability_report tool
- Add get_existing_vulnerabilities() method to tracer for fetching reports
- Update schema and system prompt with deduplication guidelines
