Release v0.7.1

[Breakthrough]

Release checklist for v0.7.1 (from RELEASE-PLAN.md). Boxes reflect current progress; this PR merges releases/0.7.1 back into main as the final step after the release is verified and published.

1. Version Identifiers, Branch Prep

• Create release branch releases/0.7.1 off main; fast-forward it to main as release work lands.
• Bump __version__ in scenedetect/__init__.py (0.7.1)
• Bump docs/LATEST_VERSION (0.7.1, matches the branch suffix so generate-docs.yml updates docs/latest)
• Regular release: no -dev suffix

2. Documentation, Website, Changelog

• Docstrings / API docs reflect any signature changes (sphinx-build completes clean).
• docs/api/migration_guide.rst reviewed - 0.7.1 is additive-only (no breaking changes), no update needed.
• Docstring examples all run correctly, nothing references removed or deprecated symbols. (Usage examples in scene_manager.py / detect() executed against a real video; fixed a stale placeholder doctest in histogram_detector.py.)
• Changelog has release notes: 0.7.1 section with summary, all features/bugfixes documented.
• website/pages/download.md updated (v0.7.1, July 2026, installer links point at the v0.7.1 tag).
• website/pages/changelog.md: 0.7.1 section moved from the Development section to the top (nested under ## PySceneDetect 0.7); fresh 0.7.2 stub left at the bottom.
• website/pages/index.md: latest release version and date updated.
• docs/cli.rst regenerated (had pre-existing drift: --frame-rate rename, save-edl --start-timecode).

3. Tests

• Static analysis passing (ruff check + format clean, pyright 0 errors).
• Unit tests green locally: 358 passed / 2 skipped in the dev venv, and again in a fresh venv with the exact Windows build pins (OpenCV 5.0.0.93, PyAV 18.0.0, numpy 2.5.1).
• Release test suite green in CI: all 4 jobs (static, release-tests, install-matrix, long-stress) on the tag. (Local pre-check: 79 passed / 3 skipped; one test needs ffprobe, which is unavailable locally - covered by CI.)
• pip-audit clean or exceptions documented in the changelog. pillow 11.3.0 (transitive via moviepy's pillow<12.0 cap, moviepy#2553) had 5 CVEs fixed only in 12.3.0: overridden to 12.3.0 in the Windows build (appveyor.yml) and Docker image (Dockerfile), noted in the changelog; full test suite passes against 12.3.0. Remaining pip audit findings are build-tooling only (not shipped). PyPI installs still resolve pillow per moviepy's cap - fixable only upstream.
• packaging/build_all.py produces all 6 artifacts at 0.7.1.

4. Prepare Windows Distribution

• packaging/windows/requirements.txt updated (OpenCV 5, PyAV 18, numpy 2.5.1, click 8.4.2, platformdirs 4.11.0, tqdm 4.69.0) and bundled ffmpeg bumped to 8.1.2 in appveyor.yml.
• scripts/update_installer.py run: .aip at ProductVersion 0.7.1, fresh ProductCode, MSI filename PySceneDetect-0.7.1-win64.msi; parity with __version__ verified.
• Run AppVeyor build on release branch, ensure resulting portable distribution and MSI installer are correct.

5. Tag & Draft Release

• Final commit on releases/0.7.1: "Release v0.7.1".
• Tag v0.7.1 on that commit and push. Wait for all tests/builds to pass.
• Approve code signing request on SignPath, download scenedetect-signed.zip
• Finalize Windows artifacts locally: drop scenedetect-signed.zip into dist/signed/, run python scripts/finalize_windows_dist.py (rebuilds portable .zip from the signed .msi, writes manifest + SHA256SUMS, runs scripts/validate_release.py).
• Draft release on Github using the tagged commit: full changelog and release notes, signed portable .ZIP, signed .MSI installer, Python .whl/.tar.gz packages, and checksum manifests (PySceneDetect-0.7.1-win64.manifest.json + SHA256SUMS)
• Verify all artifacts uploaded to Github release are valid and named correctly
• Smoke-test all release artifacts

6. Publish & Release Checks

• Dispatch release.yml (Release Orchestrator) with tag=v0.7.1 while the release is still a draft. It runs the verify-then-publish ladder (MSI install/upgrade test -> TestPyPI -> publish Github release -> PyPI -> Docker), verifying each stage before the next.
• Verify the Docker image on GHCR: ghcr.io/breakthrough/pyscenedetect:latest and the version tag.
• Verify all three projects: https://pypi.org/project/scenedetect/, https://pypi.org/project/scenedetect-headless/, and https://pypi.org/project/scenedetect-core/.
• Deploy website: generate-website.yml
• Deploy docs: generate-docs.yml
• Merge this PR (release branch back into main), verify docs/LATEST_VERSION is correct
• Manually dispatch generate-docs.yml against releases/0.7.1 to update www.scenedetect.com/docs/latest
• Smoke-test PyPI release: in a fresh venv, pip install scenedetect==0.7.1; CLI launches and scenedetect version looks correct.
• Verify download links on website are correct, PyPI project page is up to date and correct.
• Clear / archive release-scoped tracking files. (None this cycle; session scratch files were never committed.)
• Announce: project site, relevant issues / discussions closed and linked to the release.