AutoTest of Creatives v4(final)

## Block 3: Campaign Assembly

This block runs two parallel streams that converge at the end:

**Stream A (Creatives):**
- The `Merge Creatives` node gathers all processed creatives into a single, iterable list.

**Stream B (Campaign Structure):**
- `Run Once` ensures that the Campaign and Ad Set are created only once per workflow execution.
- A new Campaign is created with the `OUTCOME_SALES` objective.
- An Ad Set is created, configured for `OFFSITE_CONVERSIONS` (optimizing for the "Add to Cart" pixel event).

**Final Merge:** Using `Combine (All Possible Combinations)`, the single Ad Set ID is intelligently joined with every creative from Stream A.