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/templates/config/package.scripts.json

@@ -0,0 +1,27 @@
+{
+  "_note": "Merge these into package.json in task 01. `prepare` is what installs husky; without it every hook is inert.",
+  "scripts": {
+    "dev": "astro dev",
+    "build": "astro build",
+    "preview": "astro preview",
+    "check": "astro check",
+    "lint": "eslint . --max-warnings=0 && stylelint '**/*.css' --max-warnings=0",
+    "format": "prettier --write .",
+    "verify": "node scripts/verify.mjs && node scripts/audit-ui.mjs && node .agents/scripts/check-tokens.mjs",
+    "gate": "./.agents/scripts/gate.sh",
+    "snapshot": "node .agents/scripts/snapshot-route.mjs",
+    "prepare": "husky"
+  },
+  "devDependencies": {
+    "astro": "^5",
+    "@eslint/js": "^9",
+    "eslint": "^9",
+    "eslint-plugin-astro": "^1",
+    "husky": "^9",
+    "lint-staged": "^16",
+    "prettier": "^3",
+    "prettier-plugin-astro": "^0.14",
+    "stylelint": "^16",
+    "stylelint-config-standard": "^39"
+  }
+}