Release v3.0.1

[igerber]

Summary

• Bump version to 3.0.1 across all version locations
• Add CHANGELOG entry covering: aggregate_survey() helper, Python 3.14 support (PyO3 0.28, MSRV 1.84), domain estimation fixes
• Add missing v3.0.0 comparison link in CHANGELOG

Methodology references

• N/A — version bump only, no methodology changes in this PR

Validation

• No test changes — release bookkeeping only

Security / privacy

• Confirm no secrets/PII in this PR: Yes

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Generated with Claude Code

[github-actions]

Overall Assessment

✅ Looks good

Executive Summary

• The diff is release bookkeeping only: a new 3.0.1 changelog entry plus version bumps in CHANGELOG.md:10, diff_diff/init.py:218, pyproject.toml:7, rust/Cargo.toml:3, and docs/llms-full.txt:5.
• No estimator implementation, weighting, variance/SE logic, identification checks, or default behavior changes are introduced by this PR.
• The only methodology-adjacent text is the changelog summary of aggregate_survey(), and it matches the existing Methodology Registry entry in docs/methodology/REGISTRY.md:2303 and the helper’s docstring/implementation in diff_diff/prep.py:1315 and diff_diff/prep.py:1418.
• Version metadata is internally consistent at 3.0.1; I did not find stale 3.0.0 runtime metadata outside historical changelog entries.
• The Python 3.14 support note is consistent with the current tree: README.md:2772, pyproject.toml:11, rust-test.yml:84, and publish.yml:68.

Methodology

• No findings. Affected methods in executable code: none. The release-note text for aggregate_survey() at CHANGELOG.md:12 is consistent with the documented Lumley/domain-estimation approach in docs/methodology/REGISTRY.md:2303 and the existing zero-padded IF / SRS-fallback implementation in diff_diff/prep.py:1315.

Code Quality

• No findings. The runtime-impacting edits are limited to aligned version constants in diff_diff/init.py:218, pyproject.toml:7, and rust/Cargo.toml:3.

Performance

• No findings. No executable data path or algorithm changed.

Maintainability

• No findings. The release metadata is internally consistent, including the LLM-facing docs version in docs/llms-full.txt:5.

Tech Debt

• No findings. This PR does not add new deferred work and does not conflict with tracked review debt in TODO.md:51.

Security

• No findings. The diff adds no secrets, credentials, or new runtime surface area.

Documentation/Tests

• No findings. For a bookkeeping-only release PR, the absence of test changes is acceptable. Static review only; I did not run the test suite.