Move the engine pin to v26.7.1-rc.1

[github-actions]

The release check ran the v2 and v3 suites against v26.7.1-rc.1 on
all four platforms and they passed, so the engine can be adopted. This
moves the pin v26.7.0 → v26.7.1-rc.1.

LIBCHDB_NPM_VERSION and the @chdb/lib-<platform> pins move with it,
to 26.7.1-rc.1.1 — the version has to name the engine inside it, and the
counter restarts because this engine has not been packaged before. Merging
this does not publish anything; that is still a separate decision.

https://github.com/chdb-io/chdb-node/actions/runs/31955624296

Based on 7bceabf, the commit that run tested.

No checks will appear here. GitHub does not start workflow runs for
commits a workflow pushed with GITHUB_TOKEN, and running CI on this
branch would exercise the same suites against the same engine the check
just used.

Note

Move engine pin to v26.7.1-rc.1

Updates the CHDB_ENGINE_PIN in update_libchdb.sh and the @chdb/lib-* optional dependencies in package.json from 26.7.0-stable.1 to 26.7.1-rc.1.1.

^{Macroscope summarized 6213822.}

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[ShawnChen-Sirius]

Closed: this was opened by the release check firing on v26.7.1-rc.1, which is a pre-release. Adopting a pre-release engine is a deliberate decision rather than something a tag should propose, and the trigger has been corrected in chdb-core to fire only on full releases. The pin stays where it is.