Recover missing library artifacts from existing release tags

[nedtwigg]

The 4.10.3 library run completed its local publication tasks, then failed pushing the changelog commit to the protected release branch (run 36182812987). The Maven publishing plugin uploads its bundle only when the Gradle build finishes successfully, so the existing lib/4.10.3 tag does not mean the artifacts reached Central. The released plugins already depend on these missing libraries.

Add a lib-recover deploy option with a lib_version input. It checks out the existing library tag, verifies both project versions match the requested version, and publishes only lib and lib-extra without running changelogPush. It uses the existing protected maven-central environment and unchanged secrets, and waits for Central's PUBLISHED state. Normal deploy modes keep their existing behavior.

After merging into release, recover the missing artifacts with:

gh workflow run deploy.yml --repo diffplug/spotless --ref release \
  -f to_publish=lib-recover -f lib_version=4.10.3

Approve the protected environment deployment, then verify both 4.10.3 libraries are available on Maven Central. This recovery does not recreate the missing GitHub release entry or change the existing tag.

Validation passed:

• actionlint .github/workflows/deploy.yml and git diff --check.
• Generated both POMs at the existing lib/4.10.3 tag and checked their exact versions.
• Ran :changelogCheck at that tag.
• Dry-ran the exact recovery tasks with the version guard and mavenCentralDeploymentValidation=PUBLISHED; neither plugin publication nor changelog mutation was in the task graph.
• Verified that requesting version 4.10.4 from the 4.10.3 checkout fails before publication.

No live publishing was performed during validation.