Release forkable SCI compatibility distribution

[whilo]

Summary

Publish the forkable-world SCI work as a replikativ compatibility distribution so Spindel, Dvergr, and Simmis are not blocked on upstream review.

• retains the upstream sci.* namespaces and EPL-1.0 attribution
• adds the forkable interpreter-world implementation currently proposed in Release SCI 0.15.59 whilo/sci#2
• publishes as org.replikativ/sci version 0.15.59-replikativ.1
• documents that the upstream and compatibility coordinates must not coexist on one classpath
• restricts Clojars deployment to the exact release tag after the JVM, Node, and Linux jobs pass

The implementation head before the packaging-only commit is 653fe958bb2a792080ab5119237f6dd707efafea, matching the reviewed upstream proposal.

Verification

• script/test/jvm: Clojure 1.10.3 and 1.11.1, 427 tests / 1671 assertions each, zero failures/errors
• script/test/node: :none and :advanced, 454 tests, zero failures/errors
• lein with-profiles +compile-java do clean, jar
• generated POM identifies org.replikativ:sci:0.15.59-replikativ.1
• jar contains the fork/world namespaces and Maven metadata under the new coordinate
• git diff --check

Release

After merge, tag the merge commit replikativ-v0.15.59.1. The exact-tag CircleCI workflow deploys to Clojars using the existing clojars-deploy context.