Map zone adds gather method

[superstar54]

This PR adds the following changes:

• map_zone.item has two outputs: key and value.
• add gather method to collect the results
• use map_zone.outputs to pass data to other tasks outside the map zone

Here is an example:

@task()
def generate_data(n: int) -> Annotated[dict, namespace(data=dynamic(int))]:
    """Generate a dictionary of integers."""
    result = {f'key_{i}': i for i in range(n)}
    return {'data': result}

@task()
def add(x, y):
    """Add two numbers."""
    return x + y

@task()
def calc_sum(data: Annotated[dict, dynamic(orm.Int)]) -> float:
    """Compute the sum of all provided values."""
    return sum(data.values())


x = 1
y = 2
n = 3
with WorkGraph('add_graph') as wg:
    data = generate_data(n=n).data
    with Map(data) as map_zone:
        out1 = add(x=map_zone.item.value, y=x).result
        out2= add(x=map_zone.item.value, y=y).result
        map_zone.gather({"sum1": out1, "sum2": out2})
    out3 = calc_sum(data=map_zone.outputs.sum1).result
    out4 = calc_sum(data=map_zone.outputs.sum2).result

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.10%. Comparing base (83b0a26) to head (16993ec).
⚠️ Report is 35 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #638      +/-   ##
==========================================
- Coverage   90.87%   90.10%   -0.76%     
==========================================
  Files          44       44              
  Lines        3184     3038     -146     
==========================================
- Hits         2893     2737     -156     
- Misses        291      301      +10     

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