[yegor256]

Master has no Maven project yet. This adds only .github/workflows/maven.yml, for pull requests targeting master and pushes to master. The job runs mvn --batch-mode --no-transfer-progress clean verify with Temurin 17 and Maven 3.9.11, matching the published EO 0.58.3 plugin requirements discussed in #8. Actions are pinned, permissions are read-only, and the job has a 20-minute timeout and Maven dependency cache.

Blocked by #4: keep this draft until its POM and sources land, then sync this branch with master and verify the actual Maven check before marking ready. The workflow deliberately fails with a clear diagnostic when pom.xml is absent, rather than reporting a successful build of an empty project. No scaffold, source, or dependency changes are included; #2/#4 and dependency upgrades keep their existing owners, and #5 remains draft.

@uchitsa, please confirm clean verify as the CI command for #4 and your draft #5; it includes the clean compile acceptance check plus tests/package verification. Java 17 here is the build JDK and does not change the Java 11 compilation target in your POM. @yegor256, please resolve the #4 prerequisite with its owner before enabling this workflow.

Validation: actionlint and git diff --check pass. Maven cannot run on master until #4 supplies pom.xml. Global local hooks additionally report existing README formatting and repository-wide REUSE metadata failures; these are outside this workflow change.

Merge policy for this PR: sync with master; use gh merge immediately only when all head checks are green, the head has no conflicts, and the draft prerequisite is resolved; no review required. Never Rultor. Other PRs remain with PR maintenance.

[yegor256]

The first workflow run completed: build log. Checkout passed; Require Maven project failed because master has no pom.xml, as expected while #4 is open. Java/Maven setup and compilation were skipped after that prerequisite failure. This is a project-input blocker, not a successful Maven validation. The workflow passes actionlint and whitespace checks locally.

@yegor256, please unblock the project input with @uchitsa in #4 and confirm the proposed command; keep this PR draft until then. After #4 lands, sync this branch with master, repair any workflow failures, and use gh pr merge immediately once ready, conflict-free, and all checks on the current head are green; no review required, never Rultor. Leave #4/#5 maintenance and dependency upgrades to their existing owners. No new successor wish was created because the wish queue is capped at 100. Telegram notification was delivered.