Introducing Application-Level File System Permissions in Platformatic Watt

Platformatic Watt now supports application-level file system permissions, leveraging Node.js's native permission model to control read and write access for individual services. This feature acts as a guardrail to prevent trusted code from accidentally accessing files outside designated paths, implementing the principle of least privilege. Configuration is straightforward through JSON, with automatic node_modules access and support for environment variables. While not designed to defend against malicious code, it helps catch bugs and reduces the blast radius of coding mistakes in multi-service architectures.