fix(backend): disable OTel SDK in tests + exclude azure-resources to fix semconv conflict

opentelemetry-spring-boot-starter:2.27.0 pulls in AzureAppServiceResourceProvider which
references ServiceAttributes.SERVICE_INSTANCE_ID — a field absent from the semconv version
used by this project. This caused every integration test to fail with NoSuchFieldError during
Spring context startup.

Fix 1 (application-test.yaml): set otel.sdk.disabled=true so the OTel auto-configuration
never runs during tests at all.

Fix 2 (pom.xml): exclude opentelemetry-azure-resources from the starter dependency to remove
the problematic provider from the dependency graph entirely.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/pom.xml

@@ -215,6 +215,14 @@
 			<groupId>io.opentelemetry.instrumentation</groupId>
 			<artifactId>opentelemetry-spring-boot-starter</artifactId>
 			<version>2.27.0</version>
+			<exclusions>
+				<!-- Excludes AzureAppServiceResourceProvider which references ServiceAttributes.SERVICE_INSTANCE_ID
+				     that does not exist in the semconv version pulled by this project. -->
+				<exclusion>
+					<groupId>io.opentelemetry.contrib</groupId>
+					<artifactId>opentelemetry-azure-resources</artifactId>
+				</exclusion>
+			</exclusions>
 		</dependency>
 	</dependencies>
 

backend/src/test/resources/application-test.yaml

@@ -14,6 +14,12 @@ spring:
   mail:
     host: localhost
 
+# Disable OTel SDK entirely in tests — prevents auto-configuration from loading resource providers
+# (e.g. AzureAppServiceResourceProvider) that fail against the semconv version used here.
+otel:
+  sdk:
+    disabled: true
+
 # Disable trace export in tests — prevents OTLP connection attempts when no Tempo is running.
 # Sampling probability 0.0 means no spans are created, so no export is attempted.
 management: