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/effort-pins.txt

@@ -0,0 +1,46 @@
+# lib/effort-pins.txt — entry effort level of the vendored skills
+# (skills-external/<name>/SKILL.md). Upstream copies carry no `effort:` and
+# every resync rewrites SKILL.md, so the pin lives here and
+# lib/effort-pins.sh re-applies it after the last vendoring step of
+# install-plugins.sh and update-all.sh. One line = `<skill> <level>`,
+# level in low|medium|high|xhigh|max. The census
+# lib/tests/effort-routing.test.sh checks every vendored file against this
+# map. Rungs (BDR-107, BDR-108): low = fix a line, run a script · medium =
+# day-to-day · high = refactor, resisting bug · xhigh = architecture, audit
+# before validation · max = stuck.
+#
+# superpowers (obra/superpowers, plugins.lock.json "superpowers")
+brainstorming xhigh
+writing-plans xhigh
+requesting-code-review xhigh
+subagent-driven-development high
+writing-skills high
+test-driven-development medium
+using-git-worktrees low
+#
+# agent-skills (addyosmani/agent-skills, plugins.lock.json "agent-skills")
+deprecation-and-migration high
+ci-cd-and-automation medium
+observability-and-instrumentation medium
+#
+# design stack — ONE level for every member: these skills load stacked in a
+# single UI build and the last loaded wins (lib/effort-shift.md), so two
+# levels in the stack would make the effort depend on load order.
+# skills/site-motion (repo-authored) pins the same level in its frontmatter.
+frontend-design high
+emil-design-eng high
+design-motion-principles high
+21st-ui-build high
+scroll-world-storytelling high
+build-threejs-scroll-worlds high
+scroll-scrubbed-visual-sequence high
+scroll-scrubbed-word-reveal high
+scroll-progress-timeline high
+#
+# 21st pack (`21st skills install`): tooling low, generation high, critique xhigh
+21st-cli-use low
+21st-registry low
+21st-design-sync low
+21st-ai high
+21st-ui-explore high
+21st-ui-review xhigh