feat(server): implement ship REST endpoints with Zod validation

Adds GET/POST/PATCH/DELETE /api/ships with constraint validation (current <= max),
enum checks for maneuver_class, and cascade delete for weapons.

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

server/src/routes/health.ts

@@ -0,0 +1,7 @@
+import type { FastifyInstance } from 'fastify';
+
+export async function healthRoutes(app: FastifyInstance) {
+  app.get('/api/health', async () => {
+    return { status: 'ok', timestamp: Date.now() };
+  });
+}