Infra: Add Spring Actuator and structured JSON logging

[omatheusmesmo]

Proposed Improvement

• Integrate Spring Boot Actuator for health checks and metrics.
• Configure Logback or similar to output logs in structured JSON format for better integration with monitoring tools (ELK/Splunk).

Acceptance Criteria

• /actuator/health and other relevant endpoints exposed securely.
• Application logs follow a consistent JSON schema.

[omatheusmesmo]

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[hardikyadav12]

Assign me

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[hardikyadav12]

PR: #110