docs: align MorphStream with DataSys and restore CI

[qixinzhang2601]

What changed

• update canonical repository, badge, wiki, issue, and citation URLs to DataSysResearch/MorphStream
• document project status, Maven quick start, ecosystem ownership, contribution path, and Apache-2.0 licensing
• update the Maven workflow to target main and support manual dispatch
• remove the duplicate morph-common reactor entry
• replace JDK 11-incompatible javafx.util.Pair usage with the existing Commons Lang Pair
• make input tests hermetic with temporary files instead of maintainer-specific paths

Why

MorphStream has graduated from IntelliStream into DataSys. Its public identity, CI branch filters, build dependencies, and tests need to work from the canonical repository on a clean runner.

Validation

• GitHub Actions Maven build passes on JDK 11: run 29939844369
• both input tests pass using temporary files
• transferred repository visibility, collaborators, branch protection, workflow, environment, releases, redirects, and Git history were verified
• git diff --check passes