Add RCA (root cause analysis) for plan reports

[neoneye]

Summary

• Adds worker_plan_internal/rca/ package — a CLI tool that traces problems in PlanExe reports upstream through the pipeline DAG to find where they originated and classify the root cause
• DAG registry auto-generated from Luigi task introspection via extract_dag.py — zero maintenance when pipeline changes
• Three-phase recursive algorithm: (1) identify problems via LLM, (2) trace each upstream with dedup, (3) analyze source code at origin and classify as prompt_fixable, domain_complexity, or missing_input
• The classification feeds the self-improve loop: prompt_fixable origins can be fixed automatically by editing the prompt at that node
• Produces JSON (root_cause_analysis.json) and markdown (root_cause_analysis.md) reports, sorted by trace depth (deepest root cause first)
• Live event log (events.jsonl) for monitoring progress via tail -f
• 47 tests, all passing

Usage

python -m worker_plan_internal.rca \
    --dir /path/to/output \
    --file 030-report.html \
    --problem "The budget appears unvalidated..." \
    --verbose

Test plan

• All 47 rca tests pass
• CLI --help works
• Module is importable
• Manual test on paperclip_automation output (3 problems found, 48 LLM calls, deepest origin depth 12)
• Manual test on india_census and minecraft_escape outputs

🤖 Generated with Claude Code