chore(ci): drop redundant nightly-release-tag-v5-next workflow

[AztecBot]

What

Deletes .github/workflows/nightly-release-tag-v5-next.yml, keeping the pre-existing nightly-release-tag.yml as the single nightly tagger.

Why

The two scheduled workflows had started pushing the identical nightly tag on the public repo, so the second run of the night failed on a duplicate tag:

• nightly-release-tag.yml (4 AM UTC) — matrix tagger: public → v5-next, private → next + v5-next.
• nightly-release-tag-v5-next.yml (5 AM UTC, added in 7ac407c) — always tags v5-next on the public repo only.

Both check out v5-next and build v${manifest.version}-nightly.$(date +%Y%m%d), so on the public repo they produce the exact same tag. On the night of 2026-07-15 the 4 AM run (#497) created v5.0.0-nightly.20260715, and the 5 AM run (first-ever scheduled run) failed:

 ! [rejected]  v5.0.0-nightly.20260715 -> v5.0.0-nightly.20260715 (already exists)
error: failed to push some refs to '.../aztec-packages'
hint: Updates were rejected because the tag already exists in the remote.

7ac407c added the -v5-next.yml tagger on the assumption that nightly-release-tag.yml tagged next on public. Two days later #23984 repointed that workflow's public matrix leg from [next, v5-next] to [v5-next] ("public should not produce a next nightly tag; v6/next nightly lives on private"), which made the two workflows' public output identical.

Why drop this one (the smaller of the two)

nightly-release-tag.yml is a strict superset:

	nightly-release-tag.yml (kept)	nightly-release-tag-v5-next.yml (removed)
public (schedule)	tags v5-next	tags v5-next (duplicate)
private (schedule)	tags next + v5-next	does not run (if gate is public-only)
manual workflow_dispatch	yes (matrix)	yes (v5-next)

Removing the smaller file eliminates the duplicate-tag failure while preserving every current behaviour: the surviving workflow already tags public v5-next, private next (v6) + v5-next (v5), and keeps a workflow_dispatch button for ad-hoc runs. Deleting the other file instead would have silently dropped all private-repo nightly tagging.

Testing

Workflow-file-only change; no code paths affected. Verified the surviving nightly-release-tag.yml at the next tip still carries the full repo-dependent matrix (private → [next, v5-next], public → [v5-next]) and workflow_dispatch.

Full diagnosis: https://gist.github.com/AztecBot/9aa164d7949a3cf68c7aebaaa1333649

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Created by claudebox · group: slackbot