chore: consolidate the skill packages under .agents/

The repository had two skill directories. `skills/` held the four written
for this project; `.agents/skills/` held the ones the agent context refers
to. Nothing said which an agent should read, and `.agents/ORCHESTRATOR.md`
only ever pointed at the second.

Move the first four into `.agents/skills/` so there is one location, and
add the vendored packages this chapter work used: `animation-vocabulary`
and `improve-animations` (emilkowalski/skills), `teach` (mattpocock/skills),
plus a local `translation` skill and `audit-translations.mjs` for the EN/PT
pairs.

`skills-lock.json` pins the vendored three by source and content hash, so a
later re-vendor is a diff rather than a guess. `.claude/skills/` is
symlinks into `.agents/skills/`, which is what makes them loadable here
without a second copy on disk.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.agents/skills/editorial-playbook/references/page-anatomy.md

@@ -0,0 +1,25 @@
+# Page anatomy
+
+Use this as a compact design contract for a new AI For Dummies chapter.
+
+1. **Orientation** — eyebrow, chapter number, title, short promise, language
+   control.
+2. **Thesis** — one sentence that changes how the reader sees the topic.
+3. **Model** — a pipeline, tree, timeline, or comparison that makes the
+   relationship visible.
+4. **Practice** — a copy-ready prompt, command, example, or tiny exercise.
+5. **Proof** — source paths, checks, observed behavior, and the boundary between
+   advice and enforcement.
+6. **Transfer** — a small “use this next” link to the next chapter or deeper
+   source.
+
+Keep the first screen editorial and calm. Let code, diagrams, and controls earn
+their space by teaching something. Avoid a generic hero followed by an
+undifferentiated card grid.
+
+## Section contract
+
+Each new section should answer: what does the reader learn, what is the visible
+proof, what can they copy or try, and what source supports it? Add its copy to
+the language map before adding a control. Add its slug to navigation only after
+the section has a stable purpose.