Add Phase 1 MVP: D&D text-adventure server

FastAPI + Postgres backend with fastapi-users auth, games/characters
CRUD, and a WebSocket chat endpoint where an x.ai Grok DM narrates
play, rolls dice, and maintains character sheets via tool calls.
React + Tailwind frontend covers registration/login, game list and
creation, participation-code join flow, character viewer, and a
real-time chat session view. Docker Compose skeleton (Postgres +
backend) included; Caddy/frontend container wiring is deferred to
the deploy milestone.

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

frontend/vite.config.ts

@@ -0,0 +1,19 @@
+import react from "@vitejs/plugin-react";
+import { defineConfig } from "vite";
+
+export default defineConfig({
+  plugins: [react()],
+  server: {
+    host: true,
+    port: 5173,
+    proxy: {
+      "/api": "http://localhost:8000",
+      "/auth": "http://localhost:8000",
+      "/users": "http://localhost:8000",
+      "/ws": {
+        target: "ws://localhost:8000",
+        ws: true,
+      },
+    },
+  },
+});