feat(broker): branded react-email template for mesh invite

Replaces the plain-text invite email with a standalone react-email
template (apps/broker/src/emails/mesh-invitation.tsx) using
@react-email/components + Tailwind. Rendered on demand in
handleCliMeshInvite and sent as both HtmlBody and TextBody via
Postmark (or html+text via Resend).

Self-contained — no dependency on @turbostarter/email, i18n, or ui
packages. Adds react, react-dom, @react-email/components, @react-email/render
to broker deps. Enables tsconfig jsx: react-jsx and .tsx includes.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/broker/tsconfig.json

@@ -8,8 +8,9 @@
     "paths": {
       "~/*": ["./src/*"]
     },
-    "types": ["bun-types"]
+    "types": ["bun-types"],
+    "jsx": "react-jsx"
   },
-  "include": ["src/**/*.ts"],
+  "include": ["src/**/*.ts", "src/**/*.tsx"],
   "exclude": ["node_modules", "dist"]
 }