test(spring-boot): Port the Boot 3 OTel agent sample's Person, tracing and Todo tests

The agent tests now start the fixture app once per test JVM and share
it, because it takes seconds to start. Which mode initializes Sentry is
a property of the test task, so the suite's task runs with the agent
initializing it and a new integrationTestOtelAgentWithoutAutoInit task
runs the same tests with the Spring Boot starter doing it. Gradle runs
the two in parallel.

The fixture gains the Person POST, distributed tracing and Todo
endpoints, and the suite ports the agent sample's Person,
DistributedTracing and Todo tests. Sentry exports the agent's spans in
batches every 5 seconds, which can't be configured, so each test waits
for the next batch and the negative tracing check waits past one.

ChildJvmApp now copies the app's output into the test's as it arrives
instead of printing it on close. The shared app is closed when the JVM
exits, where its whole log would otherwise land on the console.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: runningcode

.github/workflows/spring-boot-3-matrix.yml

@@ -83,7 +83,8 @@ jobs:
             :sentry-spring-boot-jakarta:integrationTest \
             :sentry-spring-boot-jakarta:integrationTestWebflux \
             :sentry-spring-boot-jakarta:integrationTestOtelNoAgent \
-            :sentry-spring-boot-jakarta:integrationTestOtelAgent
+            :sentry-spring-boot-jakarta:integrationTestOtelAgent \
+            :sentry-spring-boot-jakarta:integrationTestOtelAgentWithoutAutoInit
 
       - name: Test sentry-samples-spring-boot-jakarta-opentelemetry agent init true
         run: |

build.gradle.kts

@@ -247,6 +247,7 @@ tasks.register("integrationTests") {
         ":sentry-spring-boot-jakarta:integrationTestWebflux",
         ":sentry-spring-boot-jakarta:integrationTestOtelNoAgent",
         ":sentry-spring-boot-jakarta:integrationTestOtelAgent",
+        ":sentry-spring-boot-jakarta:integrationTestOtelAgentWithoutAutoInit",
         ":sentry-spring-boot-4:integrationTest",
         ":sentry-spring-boot-4:integrationTestWebflux",
         ":sentry-spring-boot-4:integrationTestOtelNoAgent",