docs: add .agents workspace and the Astro refactor plan

Adds the agent-facing workspace and a 20-task plan for migrating the site
to Astro. Nothing here implements the refactor; these are briefs, rules and
templates that the task agents read.

- .agents/ holds context, rules, checklists, skills, specialist agents,
  component/page/config templates and gate scripts. It is vendor-neutral so
  MiniMax, Gemini and Codex can all read it; CLAUDE.md just points at
  AGENTS.md.
- .husky/ plus .lintstagedrc.json wire the three gate tiers. gate.sh locks on
  the shared git-common-dir so parallel worktrees serialise, and guards the
  assertion count in scripts/verify.mjs against a coverage drop.
- plans/astro-refactor/ carries the phase graph, per-task briefs and the
  model-routing recommendation.

These files must be tracked before fanning out: a worktree only checks out
tracked files, so an untracked plan is invisible to every agent working in one.

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

AGENTS.md

@@ -0,0 +1,77 @@
+# AGENTS.md
+
+Entry point for any AI agent or new engineer working in this repository. Read
+this file, then follow the links you need. Full map:
+[`.agents/ORCHESTRATOR.md`](.agents/ORCHESTRATOR.md).
+
+## What is this project?
+
+**"AI For Dummies" — a bilingual (EN/PT-BR) presentation and workshop about
+working with coding agents: model routing, subagents, git worktrees, skills,
+rules, and verification.** It is published as a static site on a self-hosted
+Gitea Pages Server, and it doubles as its own teaching artifact: the hands-on
+labs are dependency-free HTML/CSS/JS that workshop attendees point an agent at.
+
+- **Current stack**: hand-written HTML + CSS + ES modules, no build step, no dependencies
+- **Target stack**: Astro (see [`plans/astro-refactor/`](plans/astro-refactor/README.md)) — migration in progress
+- **Languages**: English and Brazilian Portuguese, toggled client-side
+- **Companion service**: `vote-service/` (Go + Kubernetes) — separate lifecycle, see its own README
+
+## Essential commands
+
+```bash
+npm run verify     # content + interaction contracts (scripts/verify.mjs) — the gate
+node scripts/audit-ui.mjs          # responsive / no-external-dependency audit
+node scripts/build-skill-review.mjs # regenerate skill-reviews/improved/ from catalog.js
+npm run serve      # python3 -m http.server 4173
+```
+
+`npm run verify` is not a formality. It is a set of ~42 string-token assertions
+that pin the site's real content and interactions. **A refactor that "passes"
+by deleting assertions has failed.** See
+[`.agents/context/verification.md`](.agents/context/verification.md).
+
+## Publishing
+
+`main` is the source of truth. The `pages` branch is what the Gitea Pages
+Server actually serves, and its tree must end up identical to `main`'s. The
+full procedure — including why `merge --ff-only` does *not* work here — is in
+[`docs/operations-guide.md`](docs/operations-guide.md).
+
+Adding a build step changes this contract. Read
+[`.agents/context/publishing.md`](.agents/context/publishing.md) before doing so.
+
+## Never touch
+
+- `hands-on/starter/` and `hands-on/rules/` — **lab fixtures.** The exercise *is*
+  that they are dependency-free vanilla HTML/CSS/JS an attendee can hand to an
+  agent. Componentizing them destroys the lesson. They ship as static assets.
+- `submitted-skills/` — other people's submitted work, reproduced verbatim
+- `skill-reviews/improved/` — generated; edit `skills-review/catalog.js` instead
+- `vote-service/` — separate deploy lifecycle; do not fold into the site build
+- `package-lock.json`, `dist/`, `node_modules/`
+
+## Rules
+
+Binding. Read the one that covers what you are about to do.
+
+| Rule | When |
+| --- | --- |
+| [`astro.md`](.agents/rules/astro.md) | any `.astro` file |
+| [`theming.md`](.agents/rules/theming.md) | any colour, font, or spacing value |
+| [`componentization.md`](.agents/rules/componentization.md) | creating or splitting a component |
+| [`animation.md`](.agents/rules/animation.md) | any motion, transition, or transform |
+| [`accessibility.md`](.agents/rules/accessibility.md) | any interactive element |
+| [`content-i18n.md`](.agents/rules/content-i18n.md) | any user-visible string |
+| [`code-style.md`](.agents/rules/code-style.md) | always |
+| [`git-worktrees.md`](.agents/rules/git-worktrees.md) | starting or finishing a task |
+
+## The one thing to understand first
+
+This site's styling is **not** a design system today. Three near-duplicate
+palettes have drifted apart (`--ink` exists as `#172f42`, `#122534`, and
+`#173044`), and the `@font-face` rule in `styles.css:1` is malformed, so the
+intended Manrope/DM Mono typography has never actually rendered. "Maintain the
+same styles" therefore needs a deliberate decision, not a copy-paste. Read
+[`.agents/context/design-system.md`](.agents/context/design-system.md) before
+touching any CSS.