chore: migrate IDE environment from Kiro to Claude Code

- Add CLAUDE.md (root + ETL subdirectory + db subdirectory) consolidating all Kiro steering docs
- Add .mcp.json migrated from .kiro/settings/mcp.json (test DBs enabled, prod disabled)
- Add .claude/commands/ (audit, doc-sync, db-docs) replacing Kiro skills
- Add .claude/hooks/ (session_start, post_edit_audit, stop_audit_check) replacing Kiro hooks
- Add .claude/settings.json registering all hooks
- Add scripts/audit/prescan.py merging Kiro's audit_flagger + compliance_prescan
- Remove .kiro/agents, hooks, scripts, settings, skills, state (migrated or obsolete)
- Update .gitignore for Claude Code

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitignore

@@ -74,17 +74,15 @@ infra/**/*.secret
 .specstory/
 .cursorindexingignore
 
+# ===== Claude Code 本地配置 =====
+.claude/settings.local.json
+
 # ===== Windows 杂项 =====
 *.lnk
 .Deleted/
 
 # ===== Kiro 运行时状态 =====
-.kiro/.audit_state.json
-.kiro/.last_prompt_id.json
-.kiro/.git_snapshot.json
-.kiro/.file_baseline.json
-.kiro/.compliance_state.json
-.kiro/.audit_context.json
+.kiro/state/
 
 # ===== 运维脚本运行时状态 =====
 scripts/ops/.monitor_token