feat(effort): entry level on every skill next to its model pin (BDR-108)

- lib/effort-pins.txt (map) + lib/effort-pins.sh (idempotent re-apply)
  replace the hardcoded brainstorming/writing-plans loop; called after the
  last vendoring step of install-plugins.sh AND update-all.sh (the resync
  dropped the pins until the next make plugin)
- design stack high uniform (last loaded wins), superpowers, agent-skills,
  21st pack pinned from the map; skills-perso low, pdf-translate medium,
  site-motion high
- doctrine: design stack loads paired with the first Read; one level per
  stack (CLAUDE.global.md, lib/effort-shift.md)
- lib/effort-audit.py prints thinking coverage per scope (sub-agent records
  carry no thinking count on ~94 % of requests)
- census map-driven + fixture suite lib/tests/effort-pins.test.sh; docs
  README/USAGE/CHANGELOG; contract + TODO plan

lib/tests/effort-pins.test.sh

@@ -0,0 +1,60 @@
+#!/usr/bin/env bash
+# lib/tests/effort-pins.test.sh — lib/effort-pins.sh's apply_effort_pins():
+# insert after `name:`, keep an equal level untouched, replace a different
+# level inside the frontmatter only (a prose `effort:` in the body stays),
+# skip a skill not vendored, insert before the closing `---` when the
+# frontmatter has no name line, run idempotently, reject a bad level, a
+# traversal name and a three-field line before writing anything, and
+# parse the real map without error. All on a throwaway fixture repo.
+set -u
+ROOT="$(cd "$(dirname "$0")/../.." && pwd)"
+LIB="$ROOT/lib/effort-pins.sh"
+pass=0; fail=0
+check() { if [ "$2" = "$3" ]; then pass=$((pass+1)); echo "PASS $1"
+  else fail=$((fail+1)); echo "FAIL $1: got[$2] want[$3]"; fi; }
+fm_effort() { awk 'NR==1&&/^---$/{p=1;next} p&&/^---$/{exit} p' "$1" \
+  | sed -n 's/^effort: //p' | head -1; }
+
+WORK="$(mktemp -d)"; trap 'rm -rf "$WORK"' EXIT
+REPO="$WORK/repo"; EXT="$REPO/skills-external"
+mkdir -p "$REPO/lib" "$EXT/alpha" "$EXT/beta" "$EXT/gamma" "$EXT/noname"
+printf -- '---\nname: alpha\ndescription: a\n---\nbody\n' > "$EXT/alpha/SKILL.md"
+printf -- '---\nname: beta\neffort: low\n---\nprose says effort: max here\n' > "$EXT/beta/SKILL.md"
+printf -- '---\nname: gamma\neffort: low\n---\nbody\n' > "$EXT/gamma/SKILL.md"
+printf -- '---\ndescription: no name line\n---\nbody\n' > "$EXT/noname/SKILL.md"
+printf '# map\nalpha high\nbeta medium\ngamma low\nghost xhigh\nnoname low\n' > "$REPO/lib/effort-pins.txt"
+gamma_before="$(cat "$EXT/gamma/SKILL.md")"
+
+bash "$LIB" "$REPO" >/dev/null 2>&1; check T1-rc-clean "$?" 0
+check T2-insert-after-name "$(sed -n '3p' "$EXT/alpha/SKILL.md")" "effort: high"
+check T3-replace-in-frontmatter "$(fm_effort "$EXT/beta/SKILL.md")" "medium"
+check T3b-body-prose-untouched "$(grep -c 'effort: max' "$EXT/beta/SKILL.md")" 1
+check T3c-single-effort-line "$(grep -c '^effort:' "$EXT/beta/SKILL.md")" 1
+check T4-equal-level-untouched "$(cat "$EXT/gamma/SKILL.md")" "$gamma_before"
+check T5-missing-skill-skipped "$([ -e "$EXT/ghost" ] && echo created || echo absent)" absent
+check T6-no-name-inserts-before-closing "$(sed -n '3p' "$EXT/noname/SKILL.md")" "effort: low"
+check T6b-no-name-still-frontmatter "$(fm_effort "$EXT/noname/SKILL.md")" "low"
+snap="$(cat "$EXT"/*/SKILL.md)"
+bash "$LIB" "$REPO" >/dev/null 2>&1
+check T7-idempotent "$(cat "$EXT"/*/SKILL.md)" "$snap"
+check T7b-no-tmp-left "$(find "$EXT" -name '*.tmp' | wc -l)" 0
+
+# rejections: nothing written, rc 1
+for bad in 'alpha turbo' '../evil high' 'alpha high extra'; do
+  printf '%s\n' "$bad" > "$REPO/lib/effort-pins.txt"
+  out="$(bash "$LIB" "$REPO" 2>&1)"; rc=$?
+  check "T8-rejected[$bad]-rc" "$rc" 1
+  check "T8-rejected[$bad]-named" "$(printf '%s' "$out" | grep -c 'rejected map line')" 1
+done
+check T8b-tree-unchanged-after-rejections "$(cat "$EXT"/*/SKILL.md)" "$snap"
+check T8c-no-evil-dir "$([ -e "$WORK/evil" ] && echo created || echo absent)" absent
+
+# the real map parses: fixture repo with the real map and no vendored skill
+mkdir -p "$WORK/real/lib" "$WORK/real/skills-external"
+cp "$ROOT/lib/effort-pins.txt" "$WORK/real/lib/"
+out="$(bash "$LIB" "$WORK/real" 2>&1)"; check T9-real-map-parses "$?" 0
+check T9b-real-map-nothing-applied "$(printf '%s' "$out" | grep -c '0 applied, 0 already')" 1
+check T10-missing-map-rc "$(bash "$LIB" "$WORK/nowhere" >/dev/null 2>&1; echo $?)" 1
+
+echo "effort-pins: $pass pass, $fail fail"
+[ "$fail" -eq 0 ]