[shiplog/plan] Add triage performance benchmarks to README

[devallibus]

Context

The triage scan workflow (#102) was motivated by a measured inefficiency: triaging 8 open issues required 11+ API calls, ~40 KB of tokens, and ~4 minutes of agent time. After implementing triage envelope fields and lifecycle labels, the same operation takes 2 API calls, ~400 B of parsed data, and <1 second.

These before/after numbers are concrete, reproducible, and demonstrate shiplog's value proposition for agent-driven workflows. The README should surface this — it's the kind of metric that helps users decide whether shiplog is worth adopting.

Design Summary

• Add a "Performance" or "How it helps" section to the README with the triage scan benchmark
• Use the real numbers from the [shiplog/plan] Add triage-scan workflow with envelope triage fields and lifecycle labels #102 session as the baseline comparison
• Keep it concise — a single table plus one paragraph of context
• Frame it as "what shiplog saves you" rather than raw numbers

Approach

Single edit to README.md — add a benchmark section. Place it after the feature overview and before installation/setup, so it serves as motivation before the user commits to installing.

Benchmark Data (from #102 session)

Metric	Without triage fields	With triage fields
API calls to triage 8 issues	11+ (individual body fetches)	2 (1 bulk list + 1 PR cross-ref)
Token input to agent	~40 KB	~400 B (envelope data only)
Wall time	~4 minutes	<1 second
Readiness visible at list level	No	Yes (lifecycle labels)
Task completion visible without body read	No	Yes (envelope triage fields)
Label-only filter ("show me ready issues")	Not possible	gh issue list --label shiplog/ready

Tasks

• T1: Add benchmark section to README [tier-3]
  • What: Add a concise performance section to README.md with the triage scan benchmark table and a brief paragraph explaining what the numbers mean. Check the current README structure to determine the best placement.
  • Files: README.md (modify)
  • Allowed to change: New section insertion in README
  • Must not change: Existing sections' content or structure
  • Verification: Read the updated README and confirm the benchmark table is present and accurate
  • Accept when: The README shows concrete before/after numbers that demonstrate shiplog's value for agent-driven triage

---

Authored-by: claude/opus-4.6 (claude-code)
Captain's log entry created by shiplog