feat: production deployment setup and hardcoded URL fixes

- Fix hardcoded localhost:8000 URLs in frontend to use relative /api/v1
  path (works with Nginx proxy in prod and VITE_API_URL in dev)
- Create production entrypoint (entrypoint.prod.sh) that runs migrations,
  seeds, and starts uvicorn with 4 workers (no --reload)
- Create comprehensive install.sh script for production deployment that
  generates secure .env, builds containers, waits for health, and
  optionally triggers initial MITRE sync
- Update docker-compose.prod.yml to use production entrypoint
- Update Dockerfile to make both entrypoints executable
- Remove init.ps1 (production will always be Linux)
- Update README with production deployment instructions

frontend/src/pages/TestCreatePage.tsx

@@ -19,7 +19,8 @@ export default function TestCreatePage() {
     queryFn: async () => {
       // We need to find the mitre_id from the technique list
       // This is a workaround since we get UUID but need mitre_id
-      const response = await fetch(`http://localhost:8000/api/v1/techniques`, {
+      const apiBase = import.meta.env.VITE_API_URL || "/api/v1";
+      const response = await fetch(`${apiBase}/techniques`, {
         headers: {
           Authorization: `Bearer ${localStorage.getItem("token")}`,
         },