fix(sec): address MEM-19 input validation and error sanitization

[ducnmm]

This PR addresses the security findings outlined in MEM-19:

• Input Validation: Enforces a maximum of 20 extracted facts (MAX_ANALYZE_FACTS) and limits individual fact length to 500 characters. Validates Sui addresses for the owner field in the sidecar. Implemented validate_namespace validation across all relevant endpoints.
• Error Sanitization: Prevents leaking internal infrastructure details (like connection strings or raw API errors) to the client. Returns generic error messages and logs detailed errors internally with a unique Correlation/Reference ID.
• Rate Limiting Adjustment: Adjusted the rate limit weighting for the /api/analyze endpoint to use a base weight of 5 and an additional weight of 2 per extracted fact.