Update Gradle to v9

Author: renovate[bot]

Dockerfile

@@ -1,7 +1,7 @@
 # ────────────────────────────────
 # Stage 1  — Build the fat JAR
 # ────────────────────────────────
-FROM gradle:8.14-jdk21 AS builder
+FROM gradle:9.3-jdk21 AS builder
 WORKDIR /app
 COPY . .
 # use the wrapper and skip tests for faster local build

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.14.3-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.3.1-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME