Function initialize_queue_workers 

pub async fn initialize_queue_workers(
    app_state: ThinData<DefaultAppState>,
    handle: Handle,
) -> Result<Vec<WorkerHandle>>

Creates the queue backend and initializes all workers in a single step.

This consolidates queue backend creation (from QUEUE_BACKEND env var), worker initialization, and logging into a single bootstrap function, keeping main.rs free of queue implementation details.

Arguments

• app_state - Application state containing the job producer and configuration
• handle - Handle to the multi-thread pipeline runtime; workers are spawned onto it so pipeline work is distributed across its worker threads.

Returns

Vector of worker handles for all spawned workers