Fix Docker build and production server infrastructure

- Add SKIP_ENV_VALIDATION to bypass Zod env check during next build
- Bundle custom server.ts with esbuild so production uses Socket.io
- Create worker entry point (src/worker.ts) with all BullMQ workers
- Add esbuild build scripts for server and worker bundles
- Fix Dockerfile.worker to include its own build stage
- Fix pre-commit hook to work without global pnpm
- Add CLAUDE.md with project conventions and quick reference

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

src/lib/env.ts

@@ -52,6 +52,10 @@ const envSchema = z.object({
 export type Env = z.infer<typeof envSchema>;
 
 function validateEnv(): Env {
+  if (process.env.SKIP_ENV_VALIDATION === '1') {
+    return process.env as unknown as Env;
+  }
+
   const result = envSchema.safeParse(process.env);
   if (!result.success) {
     console.error('Invalid environment variables:');