Task: Generate release tags as v-

TASK-DESCRIPTION

Modify: scripts/release-publish.sh
Modify: tests/81-release-publish.sh
Modify: README.md
Modify: prompts/tasks/00-tasks.md
Modify: TODO.md

When release-publish.sh has to invent a tag, it must use v<date>-<branch>, with the build date in YYYY-MM-DD form and the current branch, for example v2026-10-21-master. A tag already on the commit is still reused, an explicit TAG still overrides the generated one, and a checkout that is not on a branch is refused with a request to set TAG rather than guessing.

The release-publish test must publish without a TAG and assert the generated form, then re-publish with the same tag and assert the assets are re-uploaded. Existing published tags are not renamed.

TASK-OUTPUT

Produce these complete files in this order, then the VERIFICATION: line: 1. scripts/release-publish.sh 2. tests/81-release-publish.sh 3. README.md 4. prompts/tasks/00-tasks.md 5. TODO.md

TASK-CONTEXT

The version string is still the build-time <date>-<branch>-<hash>; the tag is the human-facing name and carries only date and branch. Two releases from the same branch on the same day therefore collide, and the second refuses unless TAG names a distinct tag.

Do not move or rename an existing published tag as part of this change.

TASK-FILES

Operation	Path
modify	`scripts/release-publish.sh`
modify	`tests/81-release-publish.sh`
modify	`README.md`
modify	`prompts/tasks/00-tasks.md`
modify	`TODO.md`

TASK-VERIFY

Run: make test from the repository root.
Expected: exit status 0, with 81-release-publish reporting ok.
Run: sh scripts/release-publish.sh from a clean scratch repository with no tag on HEAD.
Expected: the created tag matches v<date>-<branch> and is pushed with the branch.

OUTPUT: the complete files in the order listed, ending with the VERIFICATION: line.