fix(packaging): canonical SPDX license expression (0.1.7)

[t0kubetsu]

Problem

pyproject.toml declared license = "GPL-3.0". That is a deprecated SPDX
identifier: setuptools warns on it and PyPI validates license expressions, so the
correct spelling is GPL-3.0-only (or GPL-3.0-or-later). The license itself is
not changing — only its machine-readable form.

The build requirement was also under-constrained at setuptools>=68. This file
already relies on PEP 639 — a string license holding an SPDX expression, plus
license-files — which setuptools only implements from 77. Versions 68-76
reject a string license value, so a build in a clean environment could resolve
a setuptools too old to understand this metadata and fail. It works locally only
because pip's build isolation happens to fetch a current setuptools.

Change

• license = "GPL-3.0-only"
• requires = ["setuptools>=77", "wheel"]
• Version bumped to 0.1.7 in pyproject.toml and the __init__.py fallback
  literal, with the matching CHANGELOG.md section and comparison links.

No source code, API or behaviour changed.

Verification

283 tests passed
ruff check     -> All checks passed!

The equivalent change was verified end-to-end on a built wheel
(License-Expression: GPL-3.0-only, dist-info/licenses/LICENSE present).

Part of an org-wide sweep: every module carried the same deprecated identifier.
Follows quantumvalidator, which shipped this in v0.6.4.

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Review details

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📥 Commits

Reviewing files that changed from the base of the PR and between 7422ca6 and b0e8034.

📒 Files selected for processing (3)

• CHANGELOG.md
• chainvalidator/__init__.py
• pyproject.toml

---

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[greptile-apps]

Greptile Summary

This PR corrects and synchronizes the package’s release metadata.

• Replaces the deprecated GPL-3.0 identifier with the canonical GPL-3.0-only SPDX expression.
• Raises the minimum setuptools version to 77 for PEP 639 metadata support.
• Bumps the package and fallback versions to 0.1.7 and adds the corresponding changelog entry and comparison links.

Confidence Score: 5/5

The PR appears safe to merge with no actionable defects identified.

The packaging requirement now matches the metadata features in use, the SPDX expression is canonical, and all repository version declarations and release references are synchronized.

Important Files Changed

Filename	Overview
pyproject.toml	Updates the build backend requirement, canonicalizes the license expression, and bumps the package version consistently.
chainvalidator/init.py	Synchronizes the source-tree fallback version with the new package version.
CHANGELOG.md	Documents the packaging corrections and adds consistent 0.1.7 release comparison links.

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