chore(release): v7.17.0

[Data-Wise]

Version bump for v7.17.0. Minor: 2 feat, 3 fix, no breaking changes since v7.16.0.

What ships

teach deploy safety (the substance of this release)

• --dry-run is genuinely read-only — no longer aborts in CI mode (which every non-TTY caller
  gets), no longer prompts to commit, and names the uncommitted files its plan excludes. The
  prompt mattered: a pty wrapper auto-accepted it and created a real commit in a live course repo.
• --direct merges with --no-ff, so a deploy is one revertable commit again and --rollback
  can undo a multi-commit deploy as a unit.

Plus em undo / em move --recent, and the CI coverage work from #506.

Mechanics

• scripts/release.sh 7.17.0 → package.json, CLAUDE.md, flow.plugin.zsh, README badge, 20 man pages
• Both changelogs cut [7.17.0] with identical bodies; test-changelog-parity.zsh confirms [Unreleased] parity
• docs/index.md updated by hand — release.sh does not touch it, so its "What's New" banner and
  footer still advertised v7.16.0. Worth folding into release.sh so the next release doesn't repeat it.

Verification

grep 7.16.0 (excl. changelogs/release archives)  → no matches
tests/test-manpage-version-sync.zsh              → 12/12 passed
mkdocs build --strict                            → exit 0
tests/run-all.sh                                 → 82 passed, 2 failed

Both failures (e2e-em-dispatcher, test-atlas-contract) reproduce on unmodified dev and are
green in CI — local environment, not this branch.

Note

Running the suite locally mutates tracked files (.STATUS gains fake "wins" entries,
tests/fixtures/demo-course/.teach/concepts.json changes). Caught at staging and restored, so
they are not in this diff — but it's a hygiene bug someone will commit by accident eventually.