feat: integrate jquant_data_sync concept sector data

feat: add index_weight monthly update and improve SKILL.md documentation

merge: resolve conflict with remote, keep both PIT support and Factor Validation docs

docs: 更新 PIT (Point-in-Time) 数据支持文档

feat: 支持申万行业成分 PIT (Point-in-Time) 数据

docs: add code quality fixes implementation plan and update CLAUDE.md

test: add core module tests for DuckDBManager

fix: mask token in logs to prevent security leak

fix: change log level from error to info for create SQL execution

fix: SQL injection risk in get_cache_metadata method

fix: remove duplicate import time statement

fix: correct API usage in init_data.py

fix: 修复 init_data.py 废弃 API 引用

docs: add implementation plan for extending factor library and mega-scale validation

chore: add .worktrees to gitignore