normalize project structure: src/client + src/server + src/shared

- restructure from src/ + server/ to src/client/ + src/server/ + src/shared/
- switch backend runtime from Node (tsx) to Bun
- merge server/package.json into root, remove @hono/node-server + tsx
- convert server @/ imports to relative paths
- standardize biome config (lineWidth 80, quoteStyle double)
- add CLAUDE.md, .env.example at root
- update vite.config, tsconfig, deploy.sh for new structure

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

vitest.config.ts

@@ -10,11 +10,10 @@ export default defineConfig({
 		environment: "jsdom",
 		globals: true,
 		setupFiles: [],
-		exclude: ["node_modules/**", "server/**"],
 	},
 	resolve: {
 		alias: {
-			"@": resolve(__dirname, "src"),
+			"@": resolve(__dirname, "src/client"),
 		},
 	},
 })