Monorepo-wide version-catalog upgrade to latest GA (junit 6 / HikariCP 7 / flyway 12 + minors)

Bring the shared gradle/libs.versions.toml to latest GA across every JVM module (treasury, treasury-api, business, business-api, treasury-api-plugin, treasury-rest-api, chestshop, economy-flyway). Companion to PAR-269 (treasury-rest-api → Spring Boot 4.1) and in the spirit of PAR-241 (Gradle 9.6) — filed under the core build because it touches all modules.

Bumps applied

Majors: junit 5.13.3 → 6.1.0, HikariCP 6.2.1 → 7.1.0, flyway 10.22.0 → 12.9.0. Minor/patch: jjwt 0.12.6 → 0.13.0, mariadb4j 3.2.0 → 3.3.1, mockito 5.14.2 → 5.23.0, mybatis 3.5.16 → 3.5.19, mybatis-guice 4.0.0 → 4.1.0, mariadb driver 3.5.2 → 3.5.9, lombok 1.18.34 → 1.18.46, jetbrains-annotations 24.0.0 → 26.1.0, assertj 3.26.3 → 3.27.7, log4j 2.20.0 → 2.26.0, slf4j 2.0.16 → 2.0.18, jacoco 0.8.12 → 0.8.15.

Deliberately NOT bumped (no GA / version-tied)

• assertj 4.0.0-M1, log4j 3.0.0-beta, slf4j 2.1.0-alpha — pre-release only; held at latest GA (3.27.7 / 2.26.0 / 2.0.18). assertj 3.x→4 would also clear the residual catchThrowableOfType deprecation; defer until 4.0 GA.
• guice 7.0.0, reflections 0.10.2 — already latest.
• paper 1.21.11, luckperms 5.4, hibernia 1.2.0-SNAPSHOT — tied to the Minecraft/server runtime, not version-catalog hygiene.

Validation

• All modules compile (main + test) against the new majors — no API breakage from junit 6 / HikariCP 7 / flyway 12 / jjwt 0.13 / mockito 5.23.
• Runtime green on every test suite runnable on the dev box: treasury-rest-api full build incl. its MariaDB4j IT (junit-6 runtime + jjwt-0.13 verify), plus treasury-api / business-api / chestshop / treasury-api-plugin unit suites (junit-6 + mockito-5.23 + assertj-3.27 discovery/execution).
• ⚠️ Not validated locally: the embedded-MariaDB4j ITs in the treasury/business plugins (and their 95% jacoco gates, which count ITs). They fail environmentally on this Windows dev box — mysql_install_db.exe … database creation failed, MariaDB4j can't initialise — independent of any dependency change. CI must confirm these before release.

Follow-up

Watch flyway 12's behaviour against the V1–V18 migrations in the treasury/business migration-runner ITs on CI (flyway 10→12 spans two majors); confirm HikariCP 7 pool defaults are unchanged for the plugin DataSourceProviders.