🛡️ Sentinel: [security improvement] Add CORS and TrustedHost middlewares

[lgcorzo]

🛡️ Sentinel: [security improvement]

Context: The FastAPI application was missing CORSMiddleware and TrustedHostMiddleware, which are essential for security in web applications.

Changes:

• Added CORSMiddleware and TrustedHostMiddleware to src/regression_model_template/controller/kafka_app.py.
• Introduced ALLOWED_ORIGINS and ALLOWED_HOSTS environment variables for configuration.
• Defaulted ALLOWED_ORIGINS and ALLOWED_HOSTS to * to maintain backward compatibility, but allow operators to restrict access.

Verification:

• Verified that middlewares are present and correctly configured using a temporary test script.
• Ran existing security tests (tests/controller/test_kafka_app_security.py) and full checks (poetry run invoke checks).

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PR created automatically by Jules for task 4241211773520171717 started by @lgcorzo

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