fix: correct awkward backend field-leak, behavior, and dict-input bugs

[henryiii]

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Part of #711.

Fixes several bugs in the Awkward backend (each verified before/after).

1. _wrap_result leaked stale px/py fields (HIGH)

The five per-branch "extra field" exclusion tuples in _wrap_result omitted the px/py momentum aliases, so the pre-computation px/py were carried into the output alongside the freshly computed x/y.

vector.register_awkward()
arr = ak.zip({"px": [1.0], "py": [2.0], "pz": [3.0]}, with_name="Momentum3D")
arr.rotateZ(0.1).fields  # before: ['x','y','px','py','pz']  -> after: ['x','y','pz']

Fixed structurally: the five hand-copied tuples are replaced with shared, geometry-tiered module-level frozensets (_azimuthal_fields, _longitudinal_fields, _temporal_fields and their unions) that include all generic and momentum-alias coordinate names. The tiering is preserved per branch (a pure-azimuthal return still carries longitudinal/temporal coordinates as extras).

2. Record methods lost behavior (MEDIUM)

When inputs are ak.Records/scalars, _wrap_result rebuilds length-1 arrays via ak.Array(...), which dropped the behavior dict. Without global registration the output was a behavior-less Record, so chaining a second method raised AttributeError.

# no register_awkward()
r = vector.Array([{"x":1.0,"y":2.0,"z":3.0}])[0].rotateZ(0.1)
r.rotateZ(0.1)  # before: AttributeError: no field named 'rotateZ'

Fixed by capturing the input record's behavior and passing it to the ak.Array(...) rebuilds. Regression test runs in a subprocess so global registration state cannot leak in.

3. vector.Array(dict) crashed (MEDIUM)

The docstring promises all ak.Array signatures, but only list/ndarray args were converted; a dict-of-columns raised AttributeError: 'dict' object has no attribute 'type'.

vector.Array({"x":[1.0,2.0],"y":[3.0,4.0]})  # before: AttributeError -> after: VectorArray2D

Fixed by also converting dict inputs via awkward.Array(...) (dask arrays still pass through unchanged).

4. __builtins__["zip"] (LOW)

dict(__builtins__["zip"](...)) relied on __builtins__ being a dict (a CPython implementation detail). Replaced with import builtins + builtins.zip(...).

5. Dead behavior-mutation loop (LOW)

The loop in vector.Array that set .behavior on temporary projected column arrays had no observable effect, since the final awkward.with_name(..., behavior=...) unconditionally replaces the output behavior. Removed.

Docstring fixes

Corrected copy-pasted docstrings: TemporalAwkward ("longitudinal" -> "temporal"), VectorAwkward4D (described itself as a momentum class), MomentumAwkward2D/3D/4D cross-references (Vector/Momentum swapped), and MomentumArray2D.allclose ("MomentumArray4D" -> "MomentumArray2D").

Tests

Added regression tests to tests/backends/test_awkward.py covering all five fixes. Full suite (--ignore=tests/test_notebooks.py): 817 passed, 3 skipped (dask_awkward/optree/jax not installed). Doctests and prek -a pass.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.13%. Comparing base (3e32955) to head (0c83531).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #718      +/-   ##
==========================================
+ Coverage   87.09%   87.13%   +0.03%     
==========================================
  Files          96       96              
  Lines       11231    11229       -2     
==========================================
+ Hits         9782     9784       +2     
+ Misses       1449     1445       -4     

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