chore: update docs and config for PostgreSQL/OpenSearch storage layer

- Set failsafe reuseForks=true to reuse JVM across IT classes (faster test suite)
- Replace ClickHouse with PostgreSQL+OpenSearch in docker-compose.yml
- Remove redundant docker-compose.dev.yml
- Update CLAUDE.md and HOWTO.md to reflect new storage stack

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-app/pom.xml

@@ -174,7 +174,7 @@
                 <artifactId>maven-failsafe-plugin</artifactId>
                 <configuration>
                     <forkCount>1</forkCount>
-                    <reuseForks>false</reuseForks>
+                    <reuseForks>true</reuseForks>
                 </configuration>
                 <executions>
                     <execution>