chore: migrate to Spring Boot 4 (#3804)

## Summary

Migrates the Tolgee platform backend from **Spring Boot 3 to Spring Boot
4** (Spring Framework 7). This is a large, cross-cutting framework
upgrade; opening as a **draft** while the test suite is brought fully
green.

Core version bumps:

| Area | From → To |
|------|-----------|
| Spring Boot | 3.x → **4.1.0** |
| Spring Framework | 6 → **7** |
| Hibernate ORM | 6 → **7.4.1** |
| Spring Data | 3 → **4** |
| Spring Batch | 5 → **6** |
| Spring Security | 6 → **7** |
| Jackson | 2 (`com.fasterxml`) → **3 (`tools.jackson`)** |
| Redisson | 3.27 → **4.6.1** |
| Spring Cloud Azure | 5.x → **7.3.0** |
| Kotlin | → **2.3.21** |
| Gradle | → **9.6.0** |

## Notable migration work

- **Autoconfigure package splits** — Boot 4 splits the autoconfigure
monolith into per-module packages (data-redis, hibernate, persistence,
security, servlet, webmvc-test, restclient, liquibase, …); imports and
excludes updated accordingly.
- **Jackson 2 → 3** — moved to `tools.jackson` coordinates and APIs;
annotations remain on `com.fasterxml.jackson.annotation`.
- **Liquibase** — Boot 4 moved Liquibase auto-configuration to a
separate `spring-boot-liquibase` module; added it so the custom
`SpringLiquibase` beans run before the `EntityManagerFactory`.
- **Redisson 4.x** — extend `RedissonAutoConfigurationV4`, exclude the
new unconditional V4 autoconfig, add `redisson-spring-cache` (split out
of core), and declare `micrometer-core` explicitly (Redisson 4 marks it
optional).
- **Hibernate 7 HQL** — added explicit `select` clauses to join queries
that no longer infer a result type.
- **JSONB attributes** — restored JSON-based deep-copy for
non-`Serializable` values (hypersistence-utils 3.15 dropped that
fallback).
- **JPA auditing / startup ordering** — wire the date-time provider via
`dateTimeProviderRef` and defer DB access out of bean construction,
since Boot 4 creates servlet-filter beans before Liquibase migrates.

### Upstream bug found

Hibernate 7's `hibernate-models` crashes with
`IndexOutOfBoundsException` on a JSONB entity attribute whose type is a
`Map` subclass reaching `Map<K,V>` through a one-type-parameter generic
intermediate. Reported upstream:
hibernate/hibernate-models#263 (worked around
in `CompactSharedMap`).

## Status

- ✅ Full backend compiles (all modules)
- ✅ Application boots end-to-end (context loads, Liquibase migrates, web
server starts, batch jobs execute)
- ✅ Core integration tests green (e.g.
`BatchJobsGeneralWithoutRedisTest`)
- ⏳ Widening test-suite coverage; the Redis-backed concurrent batch
tests (`BatchJobsGeneralWithRedisTest`, `BatchJobRecoveryTest`, …) are
pre-existing flaky/timing-sensitive tests still being verified

## Related

The matching `billing` branch (`bdshadow/spring-boot-4`) carries the
corresponding billing changes.

Author: bdshadow

.github/actions/setup-env/action.yaml

@@ -32,7 +32,7 @@ runs:
       if: "${{ inputs.java == 'true' }}"
       uses: actions/setup-java@v4
       with:
-        java-version: 21
+        java-version: 25
         distribution: temurin
 
     - name: Setup Gradle

.github/workflows/prerelease-alpha.yml

@@ -14,7 +14,7 @@ jobs:
 
       - uses: actions/setup-java@v3
         with:
-          java-version: 21
+          java-version: 25
           distribution: adopt
 
       - name: Setup node

.github/workflows/preview.yml

@@ -16,7 +16,7 @@ jobs:
 
       - uses: actions/setup-java@v3
         with:
-          java-version: 21
+          java-version: 25
           distribution: adopt
 
       - name: Setup node

.github/workflows/release.yml

@@ -18,7 +18,7 @@ jobs:
 
       - uses: actions/setup-java@v3
         with:
-          java-version: 21
+          java-version: 25
           distribution: adopt
 
       - name: Setup node

backend/api/build.gradle

@@ -27,13 +27,13 @@ apply plugin: 'io.spring.dependency-management'
 
 java {
     toolchain {
-        languageVersion = JavaLanguageVersion.of(21)
+        languageVersion = JavaLanguageVersion.of(javaVersion.toInteger())
     }
 }
 
 kotlin {
     compilerOptions {
-        freeCompilerArgs.addAll("-Xjsr305=strict")
+        freeCompilerArgs.addAll("-Xjsr305=strict", "-Xannotation-default-target=param-property")
     }
 }
 
@@ -59,6 +59,7 @@ dependencies {
     implementation libs.springDocWebmvcApi
     implementation libs.springDocOpenApiUi
     implementation libs.redissonSpringBootStarter
+    implementation libs.redissonSpringCache
 
     /**
      * Misc

backend/api/src/main/kotlin/io/tolgee/api/v2/controllers/suggestion/MtResultStreamer.kt

@@ -1,6 +1,5 @@
 package io.tolgee.api.v2.controllers.suggestion
 
-import com.fasterxml.jackson.databind.ObjectMapper
 import io.sentry.Sentry
 import io.tolgee.constants.MtServiceType
 import io.tolgee.dtos.cacheable.ProjectDto
@@ -27,6 +26,7 @@ import kotlinx.coroutines.runBlocking
 import org.springframework.context.ApplicationContext
 import org.springframework.security.core.context.SecurityContextHolder
 import org.springframework.web.servlet.mvc.method.annotation.StreamingResponseBody
+import tools.jackson.databind.ObjectMapper
 import java.io.OutputStream
 import java.io.OutputStreamWriter
 

backend/api/src/main/kotlin/io/tolgee/component/EnumNameKryo5Codec.kt

@@ -10,8 +10,11 @@ class EnumNameKryo5Codec : Kryo5Codec {
   /** Redisson reflectively requires a `(ClassLoader, <this exact type>)` constructor to rebind the codec. */
   constructor(classLoader: ClassLoader?, codec: EnumNameKryo5Codec) : super(classLoader, codec)
 
-  override fun createKryo(classLoader: ClassLoader?): Kryo {
-    return super.createKryo(classLoader).apply {
+  override fun createKryo(
+    classLoader: ClassLoader?,
+    useReferences: Boolean,
+  ): Kryo {
+    return super.createKryo(classLoader, useReferences).apply {
       addDefaultSerializer(Enum::class.java, EnumNameSerializer::class.java)
     }
   }

backend/api/src/main/kotlin/io/tolgee/component/KeyComplexEditHelper.kt

@@ -1,6 +1,5 @@
 package io.tolgee.component
 
-import com.fasterxml.jackson.databind.ObjectMapper
 import io.tolgee.activity.ActivityHolder
 import io.tolgee.activity.data.ActivityType
 import io.tolgee.constants.Message
@@ -28,6 +27,7 @@ import io.tolgee.util.executeInNewRepeatableTransaction
 import org.springframework.context.ApplicationContext
 import org.springframework.transaction.PlatformTransactionManager
 import org.springframework.transaction.TransactionDefinition
+import tools.jackson.databind.ObjectMapper
 import kotlin.properties.Delegates
 
 class KeyComplexEditHelper(

backend/api/src/main/kotlin/io/tolgee/component/ProjectLastModifiedManager.kt

@@ -36,7 +36,7 @@ class ProjectLastModifiedManager(
    * - Cache-Control header set to max-age=0 to ensure validation on each request
    *
    */
-  fun <T> onlyWhenProjectDataChanged(
+  fun <T : Any> onlyWhenProjectDataChanged(
     request: WebRequest,
     fn: (
       /**

backend/api/src/main/kotlin/io/tolgee/component/TestClockHeaderFilter.kt

@@ -3,12 +3,13 @@ package io.tolgee.component
 import jakarta.servlet.FilterChain
 import jakarta.servlet.http.HttpServletRequest
 import jakarta.servlet.http.HttpServletResponse
+import org.springframework.context.annotation.Lazy
 import org.springframework.stereotype.Component
 import org.springframework.web.filter.OncePerRequestFilter
 
 @Component
 class TestClockHeaderFilter(
-  private val currentDateProvider: CurrentDateProvider,
+  @Lazy private val currentDateProvider: CurrentDateProvider,
 ) : OncePerRequestFilter() {
   companion object {
     const val TOLGEE_TEST_CLOCK_HEADER_NAME = "X-Tolgee-Test-Clock"