chore: refactor Gradle config, standardize Kotlin MPP plugin usage, and update dependencies

- Unified plugin application across modules using `alias(libs.plugins.*)` instead of hardcoded IDs.
- Removed redundant JVM/JS source map tasks, improving Gradle and Docker build consistency.
- Updated dependencies, including `logback` and Webpack `copy-webpack-plugin`, and added contextual documentation.
- Added frontend architecture diagram in PlantUML (`docs/01_Architecture/Reference`), standardizing feature-core-shell dependencies.

backend/services/ping/ping-service/src/test/kotlin/at/mocode/ping/service/PingControllerIntegrationTest.kt

@@ -22,6 +22,7 @@ import org.springframework.test.web.servlet.MockMvc
 import org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get
 import org.springframework.test.web.servlet.result.MockMvcResultMatchers.status
 import java.time.Instant
+import kotlin.uuid.ExperimentalUuidApi
 
 /**
  * Lightweight Spring MVC integration test (no full application context / datasource).
@@ -33,6 +34,7 @@ import java.time.Instant
 @ContextConfiguration(classes = [TestPingServiceApplication::class])
 @ActiveProfiles("test")
 @Import(PingControllerIntegrationTest.PingControllerIntegrationTestConfig::class)
+@OptIn(ExperimentalUuidApi::class)
 class PingControllerIntegrationTest {
 
     @Autowired

backend/services/ping/ping-service/src/test/kotlin/at/mocode/ping/service/PingControllerTest.kt

@@ -29,6 +29,7 @@ import org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get
 import org.springframework.test.web.servlet.result.MockMvcResultMatchers.request
 import org.springframework.test.web.servlet.result.MockMvcResultMatchers.status
 import java.time.Instant
+import kotlin.uuid.ExperimentalUuidApi
 
 /**
  * Unit tests for PingController
@@ -42,6 +43,7 @@ import java.time.Instant
 @ActiveProfiles("test")
 @Import(PingControllerTest.PingControllerTestConfig::class)
 @AutoConfigureMockMvc(addFilters = false) // Disable security filters for unit tests
+@OptIn(ExperimentalUuidApi::class)
 class PingControllerTest {
 
     @Autowired