Upgrade Gradle to 9.7.0

[lagergren]

Updates the Gradle wrapper to 9.7.0 and regenerates the wrapper JAR with Gradle 9.7.0. Also removes the stale native-access Gradle JVM workaround; the build runs cleanly on Java 25 without it.

Verification:

• ./gradlew --version
• ./gradlew clean build installDist --stacktrace --console=plain --warning-mode=all --no-daemon

Notes:

• No Gradle deprecation warnings were emitted with --warning-mode=all.
• No Kotlin DSL delegated-accessor warnings were present; the Gradle build scripts do not use the affected by-delegation pattern.
• Dockerfile uses ./gradlew and has no hard-coded Gradle version. Local Docker verification is currently blocked by the host Podman socket refusing connections.