refactor(build): centralize JVM toolchain configuration in root build.gradle.kts

Removed redundant `jvmToolchain(25)` declarations across module build scripts, as the JVM toolchain is now managed centrally. Added comments for clarity.

backend/services/entries/entries-api/build.gradle.kts

@@ -7,12 +7,10 @@ group = "at.mocode"
 version = "1.0.0"
 
 kotlin {
+  // Toolchain is now handled centrally in the root build.gradle.kts
 
   val enableWasm = providers.gradleProperty("enableWasm").orNull == "true"
 
-  // Align the toolchain with a project (see composeApp uses 25)
-  jvmToolchain(25)
-
   // JVM target for backend usage
   jvm()
 

backend/services/ping/ping-api/build.gradle.kts

@@ -7,12 +7,10 @@ group = "at.mocode"
 version = "1.0.0"
 
 kotlin {
+    // Toolchain is now handled centrally in the root build.gradle.kts
 
     val enableWasm = providers.gradleProperty("enableWasm").orNull == "true"
 
-    // Align toolchain with project (see composeApp uses 25)
-    jvmToolchain(25)
-
     // JVM target for backend usage
     jvm()