tasks: CalDAV provider (Nextcloud Tasks/iOS), review reports unknown values; bump stops pointing at release (#139)

Files changed:
- CHANGES.md
- INSTALL.md
- VERSION
- instructions/dev/version-parts.md
- instructions/gtd-weekly-review/SKILL.md
- tools/CONTRACT.md
- tools/chemenu/commands/doctor.py
- tools/chemenu/commands/version_cmd.py
- tools/chemenu/review.py
- tools/chemenu/tasks/__init__.py
- tools/chemenu/tasks/caldav.py
- tools/chemenu/tasks/config.py
- tools/chemenu/tests/test_caldav.py
- tools/chemenu/tests/test_doctor.py
- tools/chemenu/tests/test_review.py
- tools/requirements.txt

instructions/dev/version-parts.md

@@ -198,7 +198,12 @@ the three-line test below is usually enough.
    never reported by anything. The 5.0.0 candidate is the case: it declared `--no-migration` for
    a TOC-verification change, then absorbed a schema removal that migrates 152 pages.
 
-7. **Review the graded list before fixing the candidate, and regrade what reads wrong.** Run
+7. **Fix the candidate only when the user asks for a release.** Whether a candidate ships is the
+   user's call, never a session's: a work package being finished is not a reason, since the
+   candidate model exists precisely so that one does not become one release. A session that
+   bumps stops at the open `-beta.N` candidate; the next `publish` then carries it without
+   triggering `release.yml`. Once the user does ask, review the graded list first, and regrade
+   what reads wrong. Run
    `tools/wikitool version regrade` with no arguments - it lists every bump at its current grade,
    numbered in rendered order. A candidate that grew over several sessions often has a bump graded
    in isolation that reads differently once the whole shape is visible; `version regrade 3 7