📝 docs(codex_skills): normalize markdown formatting

codex/skills/root-cause-tracing/SKILL.md

@@ -6,30 +6,37 @@ description: "Root cause analysis (RCA) and tracing failures back to the origina
 # Root Cause Tracing（根因溯源 / RCA）
 
 ## When to Use
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 - Incidents, regressions, flaky tests, recurring bugs
 - “Fix the symptom” patches where the underlying trigger is unknown
 - Multi-layer failures (client → service → DB → async jobs)
 
 ## Inputs（required）
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 - Evidence: logs, stack traces, metrics, failing test output
 - Timeline: when it started, what changed, rollout events
 - Scope: affected users/paths, frequency, severity
 - Verification: how to reproduce (or how to detect reliably)
 
 ## Procedure（default）
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 1. **Frame the Failure**
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    - Define expected vs actual behavior
    - Identify the earliest known bad signal
 
 2. **Trace Backwards**
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    - Walk back through layers: surface error → caller → upstream trigger
    - Look for the first point where invariants were violated
 
 3. **Find the Trigger**
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    - What input/state/sequence causes it?
    - What changed around that area (code/config/deps/data)?
 
 4. **Fix at the Right Layer**
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    - Prefer root-cause fix + defense-in-depth guardrails
    - Add regression test or a deterministic repro harness
 
@@ -38,6 +45,7 @@ description: "Root cause analysis (RCA) and tracing failures back to the origina
    - Add monitoring/alerts if appropriate
 
 ## Output Contract（stable）
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 - Summary: what broke and impact
 - Root cause: the earliest causal violation + why it happened
 - Trigger: minimal repro steps / conditions
@@ -46,6 +54,7 @@ description: "Root cause analysis (RCA) and tracing failures back to the origina
 - Follow-ups: guardrails/observability/rollout notes
 
 ## Guardrails
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 - Don’t stop at “where it crashed”; find “why the bad state existed”
 - Separate contributing factors vs root cause
 - Avoid speculative RCA; label assumptions and request missing evidence