feat(cli): add --mode flag to dora build for parallel/sequential builds

[swar09]

Summary

Closes #1570

As of now, dora build dataflow.yml builds nodes one at a time. This is safe for low-spec hardware but wastes time on capable development machines. This PR adds a --mode flag to dora build so users can opt into parallel building.

Usage

# Sequential (current default behavior, backward compatible)
dora build dataflow.yml

# Explicitly sequential
dora build --mode sequential dataflow.yml

# Parallel (faster on capable machines)
dora build --mode parallel dataflow.yml

Note

The feature is most valuable for use cases like dataflows with Python, Rust, and C/C++ nodes from separate projects.
Works for Any combination of independent build commands.
For a pure Rust workspace with all nodes inside it, the gain is minimal because Cargo itself serializes via locks.

[swar09]

I have figured out the issue which cause CI failure i will update soon .