Prepare v1.7.0 release

[aksg87]

Summary

Prepare v1.7.0 by updating the package version and citation version/date. The concept DOI is unchanged. No runtime code changes.

Release highlights

• Improve repeated-mention source alignment, with a legacy-algorithm option (Fix repeated-mention alignment with monotonic occurrence DP #485).
• Fix provider-plugin generation, schemas, and packaging (Fix provider plugin generation #513).
• Forward Gemini generation settings, including output-token limits (Forward Gemini generation settings #509).
• Surface blocked, refused, or missing-text Gemini/OpenAI responses as inference errors (Raise on model responses without text #534).
• Fix OpenAI reasoning/GPT-3.5 routing and reasoning-model API-key discovery (Route OpenAI reasoning and GPT-3.5 models #494).

Compatibility notes

• Repeated-mention spans may change. Use resolver_params={"exact_alignment_algorithm": "difflib"} for the previous exact-alignment behavior.
• Unusable model responses may now raise instead of appearing to succeed. Valid empty strings with normal completion remain allowed.
• GPT-3.5 requires use_schema_constraints=False; explicit output-token limits for OpenAI reasoning models remain a separate follow-up.

Verification

• tox -e format, uv build, twine check, and uv pip check: passed.
• Clean base-wheel, OpenAI-extra, and source-distribution installations: passed.
• Rebuilt installed-wheel unit suite: 838 passed (--import-mode=importlib, excluding live, pip-installation, and integration tests).
• Installed-wheel live tests: all 15 distinct cases passed across targeted runs, including Vertex batch extraction, GCS cache reuse, and OpenAI Batch. Default Gemini extraction with schema constraints also passed.
• Main CI after #538: Python 3.10/3.11/3.12 and 12 live tests passed. The three batch cases skipped in CI passed locally as noted above.

Before publication

This metadata-only commit includes the merged batch-test correction (#538) in its base. Release-PR and post-merge CI must pass before publication. The citation date is September 13; update it if publication happens later. This PR does not publish a release or tag.