Make the repository Jules-ready: setup script, Definition-of-Done block, build-tool pin

[rabestro]

Context

Google Jules runs tasks in an Ubuntu VM that ships OpenJDK 21, Maven and Gradle but no sbt, scalafmt, mise or brew, reads only the root AGENTS.md, and commits outside our git hooks. The first wave of the Jules-readiness programme (six Scala repositories, 2026-09-05) cut formatting failures on Jules pull requests to zero: every validation pull request passed its first CI run. The organisation inventory of 2026-09-06 found seven more JVM repositories, this one included.

Specifics here: Maven build: the Jules VM image ships JDK 21, this repository compiles with release 25, so Maven and Java 25 come from mise; the Definition-of-Done block is the Maven variant (dc-shared:definition-of-done-maven v1).

Objective

Make dicechess-bot-java Jules-ready so that a Jules task can run the repository gate inside its VM: scripts/jules-setup.sh from the shared template (dc-shared:jules-setup v3, sbt and Maven aware), the Definition-of-Done block at the top of AGENTS.md, and the build tool pinned in mise.toml; then configure the repository in the Jules app (owner) and validate with one Routine dispatch.

Definition of Done (DoD)

• mise.toml pins the build tool (sbt matching project/build.properties, or maven plus a java matching the pom release)
• scripts/jules-setup.sh is byte-identical to skills/jules-repo-readiness/templates/jules-setup.sh v3
• AGENTS.md carries the matching Definition-of-Done block within the first 40 lines
• skills/jules-repo-readiness/scripts/check-readiness.sh passes its automated checks on the merged main
• Jules app (owner): Initial Setup = bash scripts/jules-setup.sh, "Run and Snapshot" succeeded, Knowledge enabled
• Validation: the first CI run of the next Jules pull request in this repository is green; result recorded with jules-ci-audit

Non-goals

• Adopting a formatter where none exists, changing CI workflows or sources.

[rabestro]

Readiness validated

• Readiness pull request merged; check-readiness.sh on main: all automated checks pass (Definition-of-Done block at the top of AGENTS.md, scripts/jules-setup.sh template v3, build tool pinned in mise.toml).
• Owner steps done in the Jules app: Initial Setup bash scripts/jules-setup.sh → Run and Snapshot succeeded, Knowledge enabled.
• Validation dispatch: Routine issue test: pin OnnxEvaluator fallback contract (null, blank, missing and non-ONNX model paths) #19 → Jules pull request test: pin OnnxEvaluator fallback contract #20. First CI run green on the first commit d8d81fd (CI: Java), no fix-up commit; only the specified test file touched.
• jules-ci-audit since 2026-09-06T08:00Z for this repository: 0 failed gate runs.