Initial scaffold: full-stack RackMapper application

Complete project scaffold with working auth, REST API, Prisma/SQLite
schema, Docker config, and React frontend for both Rack Planner and
Service Mapper modules. Both server and client pass TypeScript strict
mode with zero errors. Initial migration applied.

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

server/types/index.ts

@@ -0,0 +1,37 @@
+import { Request } from 'express';
+
+// ---- Error handling ----
+
+export class AppError extends Error {
+  statusCode: number;
+  code?: string;
+
+  constructor(message: string, statusCode: number, code?: string) {
+    super(message);
+    this.name = 'AppError';
+    this.statusCode = statusCode;
+    this.code = code;
+  }
+}
+
+// ---- API response shape ----
+
+export interface ApiResponse<T = unknown> {
+  data: T | null;
+  error: string | null;
+  meta?: Record<string, unknown>;
+}
+
+export function ok<T>(data: T, meta?: Record<string, unknown>): ApiResponse<T> {
+  return { data, error: null, ...(meta ? { meta } : {}) };
+}
+
+export function err(message: string, meta?: Record<string, unknown>): ApiResponse<null> {
+  return { data: null, error: message, ...(meta ? { meta } : {}) };
+}
+
+// ---- Augmented request ----
+
+export interface AuthenticatedRequest extends Request {
+  user: { sub: string };
+}