feat(cli): add a map, a précis, and a size signal (WI-P4/P5/P6)

[tjdwls101010]

Why

Measured live on 2026-07-19, bytes of the emitted envelope:

command	bytes
load-delegated-criteria --budget standard	513,570
load-institutional-system --budget standard	396,609
get-law (139 articles)	276,748
get-case (one decision)	82,700

Nothing warned about any of it. The only narrowing tool was --article, which presumes you already know which article you want — and reading the whole statute to find that out is the expensive way to ask a cheap question.

(The bundle-loader figures were the plan's unmeasured item. load-delegated-criteria turned out to be the largest output in the package, larger than get-law.)

What

get-law --toc (P4) — chapter headings, article numbers and titles, deleted/moved status. No article text. 276,748 → 18,831 bytes (6.8%).

• Heading rows excluded from article_count: law.go.kr threads them through the article list tagged 전문 reusing a neighbouring article's number, and counting them inflates the very number a caller uses to judge whether a full load is affordable.
• The 제0조 move placeholder is dropped rather than forwarded — passing it through sends a caller chasing an article that doesn't exist.

--brief (P6) on cases, constitutional decisions and interpretations — blanks text/full_text, keeps the 요지. 82,700 → 14,044 bytes (17.0%). Returns the same type; a narrower one would break every consumer's field access for a difference that belongs on the envelope. flags.brief.withheld lists what was actually present, so brief mode never claims to have hidden a section the source never had.

flags.large_payload (P5) — measured on the serialized data, not guessed from a row count (139 short articles and 20 long ones differ by an order of magnitude), so it also covers commands added later. Searches are exempt: candidate breadth is what resolves ambiguity, and 20 hits already costs ~18,000 characters (§3.1 keeps display=20).

Two pre-existing defects surfaced

1. 조문내용 nested-array repr leak. When a row carries both a 장 and a 절, law.go.kr returns a nested array; str() on it produced [['제3장 …', '제1절 …']], which travelled through get-law as if it were the statute's own wording. Wrong in a way a reader cannot detect from the output.
2. The P8 smoke was green while covering nothing for load-legal-context-bundle — it passed a positional query where the parser wants --query, argparse rejected it, and exit 5 was in the allowed set. The smoke now rejects usage_error outright and exercises --toc/--brief as the separate dispatch branches they are.

Deviations from the plan's acceptance criteria

Reporting rather than contorting to hit them:

• --toc lands at 18.8KB, not ~10KB. Dropping entry_kind too would still leave ~15KB; the estimate predates measuring what 139 entries cost in JSON structure. Serialization gained an opt-in _omit_when_empty which already cut 30.3KB → 18.8KB.
• --brief lands at 17%, not ≤10%. The remaining 14KB is mostly summary (3,680 chars). Cutting it would hit the number by removing the only thing brief mode is for.

Verification

Live: full get-law fires large_payload {chars: 139078, articles: 139}; 대한민국국기법 (12 articles, 16.5KB) stays quiet; --toc renders headings correctly post-fix; --brief withholds [text, full_text].

474 deterministic tests pass (19 new).

🤖 Generated with Claude Code