fix(gates): check body-level routing targets, not just descriptions

The ADR-0020 boundary resolver (boundary_targets()/unresolved_targets())
only ever read a SKILL.md's description. A target named in the BODY -- a
dispatch table row, a "run X" step, both routine in a 900-word procedure
-- was checked by nothing. Two real instances shipped before either was
caught by reading rather than by a gate: bin/write-docs routed twice to a
deleted `to-prd` skill, and bin/triage told an agent to run a nonexistent
`/setup-matt-pocock-skills` (both fixed in 03abcff; that fix was the
symptom, this gate is the actual ask per #124).

Added a separate, narrower extractor -- body_targets() /
unresolved_body_targets() in the shared lib-boundary-resolver.sh -- rather
than reusing the description resolver at wider scope. The description
gate's sentence-level heuristics (BOUNDARY_MARKER, the follower test,
in-sentence corroboration) are tuned for a one-to-three-sentence routing
clause and misfire on dispatch-table/procedure prose in both directions,
so the body gate reads only explicit route notation (`/name`,
backticked-or-slash-prefixed `-> name` / `-> name`), already the
description gate's own unconditionally-blocking tier.

Three guards were added after running the extractor over the real
39-skill corpus and reading every hit rather than assuming the design was
correct:

- a target must be hyphenated, even in notation -- single-word citations
  like `/fork` (forge, citing Claude Code's own /fork command) and
  `/name` (skill-author, a placeholder) are not routes.
- a bare hyphenated word after any arrow is not notation -- only
  ARROW_MARKED (backticked/slash-prefixed) is used, not NOTATION_ARROW's
  bare form, so ordinary process-chain prose ("prop -> new ref ->
  re-render", caveman) is not read as a route.
- a name immediately preceded by `<` is a closing tag
  (`</what-to-do>`, grill-with-docs), not /name notation.

Wired into both consumers that must agree by contract: scripts/
skill-size-check.sh (the pre-commit hook) and factory-audit's
lib-checks-skill.sh (the audit). Verified identical findings across both
over the whole corpus.

tests/test-adr0020-targets.sh gains a dedicated section pinning the two
live true positives and all three guards. docs/spec/gates.md and
ADR-0020 get a matching amendment.

Fixes: #124
ADR: 0020

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EGHFJextYtVQseaHPDDhxB

docs/adr/0020-skill-description-and-body-context-contract.md

@@ -414,6 +414,56 @@ and rises to a blocking ERROR the moment a resolving sibling joins it. The reaso
 the point of enforcement in `_add()`'s docstring in `scripts/skill-size-check.sh` and its two
 mirrored copies, and the verdict table in `docs/spec/gates.md` states the corrected shape.
 
+## Amendment (2026-09-22): body-level routing targets are resolved too
+
+The Decision section's routing-target resolver (`boundary_targets()` / `unresolved_targets()`) reads
+the **description** only. A target named in the **body** — a dispatch table row, a "run X" step, both
+routine in a 900-word procedure — was checked by nothing. Two real instances shipped before either
+was caught: `bin/write-docs` routed twice to a deleted `to-prd` skill, and `bin/triage` told an agent
+to run a nonexistent `/setup-matt-pocock-skills`. Both were found by reading, not by a gate, during
+the #99 retrofit and its follow-up audit; both were fixed in `03abcff`. **The fix this amendment
+records is the gate, not those two edits** (issue #124).
+
+The body gate is a **separate, narrower** extractor (`body_targets()` /
+`unresolved_body_targets()`), not the description resolver reused at wider scope. The description
+resolver's sentence-level heuristics — `BOUNDARY_MARKER`, the follower test, in-sentence
+corroboration — are tuned for a one-to-three-sentence routing clause and misfire on dispatch-table
+and procedure prose in both directions: under-firing on a table row that carries no "do not" /
+"instead", over-firing on a procedure step naming a file, a CLI verb or a config key exactly the way
+a route names a skill. Retuning those heuristics for the body genre was considered and rejected as
+the harder half of the problem, with a materially worse cost of getting it wrong (a body is loaded
+on every invocation, so a false-positive-prone body gate is felt far more often than a
+false-positive-prone description gate).
+
+So the body gate reads **only** explicit route notation — `/name` and backticked-or-slash-prefixed
+`-> name` / `→ name` — already the description gate's own unconditionally-blocking tier, and nothing
+softer: no SUGGESTION tier, no bare-word forms, no corroboration. Two further restrictions, both
+earned by a real corpus false positive rather than assumed up front:
+
+- **the target must be hyphenated**, even in notation. `` `/fork` `` (`forge/SKILL.md`, citing
+  Claude Code's own `/fork` subagent command) and `` `/name` `` (`skill-author/SKILL.md`, a
+  placeholder for the skill's own name) are real corpus citations of a tool or a placeholder, not
+  routes, and both hard-FAILed with no escape hatch before this restriction. This is the same
+  "single-word targets are ordinary English" trade the Decision section already makes for the bare
+  form, extended to notation because the body genre has no boundary-sentence signal to fall back on;
+- **a bare hyphenated word after any arrow is not notation.** The description gate's own bare-arrow
+  sweep (`NOTATION_ARROW`) reads ordinary process-chain prose as a route: `caveman`'s "Inline obj
+  prop -> new ref -> re-render." dangled to `re-render` under it. The body gate uses `ARROW_MARKED`
+  instead, which requires the target to be backticked or slash-prefixed — true of the one real
+  historical target (`` -> `to-prd` ``, confirmed against `03abcff`'s diff), so this costs no real
+  coverage;
+- a target immediately preceded by `<` is a closing tag (`</what-to-do>`, `<supporting-info>` — this
+  repo's own `grill-with-docs/SKILL.md` uses these as prompt section delimiters), not `/name`
+  notation, and is discarded on that basis alone.
+
+Both consumers — `scripts/skill-size-check.sh` and `factory-audit/scripts/lib-checks-skill.sh` —
+call the shared functions independently over the same `known_targets()` universe the description
+check already computed, so a body target folds into the existing "DID NOT RUN" INFO tier rather than
+adding a second one. `tests/test-adr0020-targets.sh` pins the two live true positives, all three
+guards above, and the fenced-code-block mask; the corpus-wide dangling assertion now covers body
+targets the same way it already covered description ones. `docs/spec/gates.md`'s "Body-level routing
+targets" section states the enforced shape in full.
+
 ## Consequences
 
 **Editing any non-compliant skill now requires retrofitting it first.** At decision time, 30 of 39