Remove UP007/UP045 ignores and fix guess_field_type for UnionType

[ogenstad]

Why

Update to use modern version of optional types.

What changed

• Fix Optional[X] -> X | None and Union[X,Y] -> X | Y across branch/models.py, graph/constraints.py, graph/schema.py, and node/standard.py; remove dead UP007 ignore for core/query/**.py.

• The guess_field_type method now checks for both typing.Union and types.UnionType so that X | None fields are handled correctly at runtime in to_db/from_db after the annotation syntax change.

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Summary by cubic

Migrate type hints to PEP 604 unions (X | Y) and fix runtime type detection so X | None fields serialize/deserialize correctly. Removes now-unneeded UP007/UP045 ignores.

• Bug Fixes

  • Update guess_field_type to recognize both typing.Union and types.UnionType, ensuring X | None works in to_db/from_db.

• Refactors

  • Replace Optional[X] with X | None and Union[X, Y] with X | Y in core/branch/models.py, core/graph/{constraints.py,schema.py}, and core/node/standard.py.
  • Clean up linter config by removing UP007/UP045 ignores in pyproject.toml (including the dead core/query/**.py rule).

^{Written for commit 2c1b450. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 5 files

[codspeed-hq]

Merging this PR will not alter performance

✅ 12 untouched benchmarks

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_{Comparing pog-20260420-up-rules (2c1b450) with develop (4a132a6)}