refactor: migrate OnnxStrategy onto dicechess-engine-scala's JvmApi

[rabestro]

Context

Bumps dicechess.engine.version to 1.12.0 (the release that ships dicechess.engine.jvmapi.JvmApi, dicechess-engine-scala#558) and rewrites OnnxStrategy against it.

OnnxStrategy previously reached into surface never meant for Java consumption:

• Reflection in a static initializer to find GameState.makeMove(Move) — an @targetName-disambiguated extension method that compiles onto a synthetic Position$package class, with no ordinary Java entry point.
• An unchecked cast through Object to unwrap TurnGenerator.generateAllLegalTurnPaths's List[List[Move]] — Move is an opaque Int, erased on the JVM, so the nested Scala collection looked like List[List[Object]] of boxed integers from Java.
• Manual Either unwrapping for FenParser.parse.
• A hand-rolled moveToNotation reimplementing UCI encoding with raw bit masks.

Changes

OnnxStrategy.chooseMoves now:

• JvmApi.parseDfen(dfen) — throws IllegalArgumentException on a bad DFEN instead of an Either to unwrap.
• JvmApi.activeColor(state) — a real static entry point, no reflection.
• JvmApi.legalTurns(state) — each legal turn as its UCI micro-move sequence and the resulting GameState in one call, so scoring a candidate turn no longer needs a separate apply-loop or an unchecked cast.

Net: ~120 fewer lines, the static initializer and its reflection are gone entirely, no more hand-rolled bit-twiddling for notation.

Verification

• mise run check (Spotless + unit tests + shaded-jar package) against the real published dicechess-engine-scala_3:1.12.0 from GitHub Packages (not a local snapshot): BUILD SUCCESS, 4/4 tests pass (OnnxStrategyTest ×3, WebhookIntegrationTest ×1), unmodified.
• OnnxStrategyTest's three cases are black-box against chooseMoves() (empty DFEN → empty list; single pawn die → 1 micro-move; triple dice pool → ≤3 micro-moves) — passing unmodified is exactly the regression signal that the rewrite preserves behavior.

Out of scope

OnnxEvaluator — unaffected, it already takes GameState/int color directly (opaque Color erases to int, so no interop issue existed there to begin with). Main/Strategy — unaffected.

Closes #17

[coderabbitai]

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: f0f57d95-7487-4bca-aa8f-d5f6d3b443aa

📥 Commits

Reviewing files that changed from the base of the PR and between eb0073e and 1441181.

📒 Files selected for processing (2)

• pom.xml
• src/main/java/dicechess/bot/OnnxStrategy.java

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📝 Walkthrough

Walkthrough

The Maven dependency updates to engine version 1.12.0. OnnxStrategy replaces Scala interop and manual move handling with JvmApi parsing, legal-turn generation, final-state evaluation, and UCI move selection.

Changes

OnnxStrategy JvmApi migration

Layer / File(s)	Summary
Engine API upgrade pom.xml, src/main/java/dicechess/bot/OnnxStrategy.java	The engine version changes to 1.12.0. OnnxStrategy now uses JvmApi instead of Scala-specific integrations.
JvmApi turn selection src/main/java/dicechess/bot/OnnxStrategy.java	chooseMoves parses DFENs, obtains legal turns, evaluates final states from the active color’s perspective, selects the highest score, and returns the turn’s UCI sequence.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Sequence Diagram(s)

sequenceDiagram
  participant OnnxStrategy
  participant JvmApi
  participant OnnxEvaluator
  OnnxStrategy->>JvmApi: Parse DFEN and read active color
  OnnxStrategy->>JvmApi: Request legal turns
  JvmApi-->>OnnxStrategy: Return turns with final states and UCI sequences
  OnnxStrategy->>OnnxEvaluator: Evaluate each final state
  OnnxEvaluator-->>OnnxStrategy: Return scores
  OnnxStrategy-->>OnnxStrategy: Return highest-scoring UCI sequence

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Possibly related issues

• rabestro/dicechess-engine-scala issue 557: The change adopts the JvmApi facade introduced for Java engine integration.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the migration of OnnxStrategy to dicechess-engine-scala's JvmApi.
Description check	✅ Passed	The description explains the JvmApi migration, dependency upgrade, removed interop workarounds, verification, and unchanged scope.
Linked Issues check	✅ Passed	The changes satisfy issue #17 by using JvmApi, upgrading to 1.12.0, removing legacy interop code, and preserving the stated scope.
Out of Scope Changes check	✅ Passed	The changes are limited to the requested dependency upgrade and OnnxStrategy rewrite; OnnxEvaluator, Main, and Strategy remain unchanged.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

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