fix(buildSrc): restore agent SPI service discovery after gradle-plugins upgrade

Shadow service-file merging was incomplete for isolated agent classes, so metric exporter providers were not discoverable from the inst service path during instrumentation tests. That caused Javaagent startup failures (otel.metrics.exporter=otlp “exporter not found”) and cascaded test failures across methods, micrometer, azure-functions, and applicationinsights-web modules.

Update shadow conventions to merge service descriptors into both META-INF/services and inst/META-INF/services, restoring provider loading for the agent classloader and passing unit tests.

Author: xiang17

buildSrc/src/main/kotlin/ai.shadow-conventions.gradle.kts

@@ -5,10 +5,8 @@ plugins {
 }
 
 tasks.withType<ShadowJar>().configureEach {
-  mergeServiceFiles {
-    include("META-INF/services/**")
-    include("inst/META-INF/services/**")
-  }
+  mergeServiceFiles()
+  mergeServiceFiles("inst/META-INF/services")
 
   exclude("**/module-info.class")
   exclude("META-INF/*.SF")