feat: packages/email — Maizzle v6 + Tailwind CSS v4 HTML email templates

- New @sexy.pivoine.art/email package with @maizzle/framework@6.0.0-15
- Uses @maizzle/tailwindcss (TW v4 preset) with @theme brand tokens
  derived from the frontend's app.css oklch primary color
- LightningCSS automatically lowers oklch/lab to hex for email clients
- Real HTML template files (templates/layouts/main.html, verification.html,
  password-reset.html) — not JS template strings
- PostCSS `from` override so @import "@maizzle/tailwindcss" resolves from
  the email package's own node_modules
- Backend lib/email.ts now calls renderVerification/renderPasswordReset
  instead of inline HTML strings

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/email/package.json

@@ -0,0 +1,25 @@
+{
+  "name": "@sexy.pivoine.art/email",
+  "version": "1.0.0",
+  "private": true,
+  "main": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "exports": {
+    ".": {
+      "require": "./dist/index.js",
+      "types": "./dist/index.d.ts"
+    }
+  },
+  "scripts": {
+    "build": "tsc",
+    "dev": "tsc --watch"
+  },
+  "dependencies": {
+    "@maizzle/framework": "6.0.0-15",
+    "@maizzle/tailwindcss": "^1.2.0"
+  },
+  "devDependencies": {
+    "@types/node": "^22.0.0",
+    "typescript": "^5.9.3"
+  }
+}