fix: add setup.py fallback for legacy setuptools to resolve UNKNOWN metadata warnings

[Qubitium]

Summary

pip install logbar (and pip install PyPcre logbar datasets) was emitting repeated WARNING: Generating metadata for package logbar produced metadata for project name unknown warnings when the build ran against legacy setuptools that could not read pyproject.toml [project] metadata (e.g. system setuptools 59.6 on Ubuntu 22.04 or no-build-isolation installs). Without a setup.py fallback, the metadata came back as UNKNOWN, causing pip to discard each candidate version.

Changes

• Added setup.py with the canonical LogBar metadata (name, version, license, packages, python_requires, etc.) so legacy setuptools can build the package correctly even when it does not parse pyproject.toml.
• Marked license as dynamic in pyproject.toml and provided it through setup.py (license="Apache-2.0"). This avoids the setuptools 83+ deprecation warning for project.license as a TOML table while still being valid for setuptools>=61.
• Lowered the build-system setuptools lower bound from >=77.0.1 to >=61 since the PEP 639 SPDX feature is no longer used.

Verification

• pip install . succeeds with modern pip/setuptools build isolation.
• pip install . --no-build-isolation succeeds on fresh venvs with setuptools 59.6, 60, 61, 65, 75, 80, 82, and 83, with Name: LogBar and no license/UNKNOWN warnings.
• Local test suite passes: 157 passed, 6 skipped.

Link to Devin session: https://app.devin.ai/sessions/fd150f4dd61f470e96ff670b2dfe7649
Requested by: @Qubitium

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