Function init_resource_manager 

pub fn init_resource_manager(config: ResourceConfig) -> Result<(), String>

Initialize the global resource manager with custom configuration

Educational: Explicit Initialization Pattern

This must be called exactly once, early in main(), before any code accesses RESOURCE_MANAGER. Subsequent calls will return an error.

Why This Pattern?

• Allows CLI flags to configure resource limits
• Makes initialization explicit and debuggable
• Avoids “lazy initialization with hidden defaults”
• Better testability (each test can configure differently)

Errors

Returns error if:

• Already initialized (called twice)
• Configuration is invalid (e.g., 0 CPU threads)