test(03-02): integration tests for SSE and command endpoints

- AgentSseControllerIT: connect, 404 unknown, config-update/deep-trace/replay delivery, ping keepalive, Last-Event-ID
- AgentCommandControllerIT: single/group/broadcast commands, ack, ack-unknown, command-to-unregistered
- Test config with 1s ping interval for faster SSE keepalive testing
- All 71 tests pass with mvn clean verify

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

cameleer3-server-app/src/test/resources/application-test.yml

@@ -9,3 +9,6 @@ ingestion:
   buffer-capacity: 100
   batch-size: 10
   flush-interval-ms: 100
+
+agent-registry:
+  ping-interval-ms: 1000