Add Comprehensive Input Validation and Sanitization

[godwinameh]

Issue: User inputs including property searches, wallet addresses, and form submissions lack proper validation and sanitization, creating vectors for XSS attacks and data integrity issues.

Business Impact:

• Security vulnerabilities exposing users to XSS attacks
• Data integrity issues affecting property transactions
• Potential for injection attacks against backend services
• Compliance and security audit failures

Technical Requirements:

• Implement comprehensive input validation for all user inputs
• Add XSS protection and output sanitization
• Validate wallet addresses and transaction parameters
• Implement rate limiting and abuse prevention
• Add content security policy (CSP) headers
• Establish security testing and vulnerability scanning

Files: All form components, search functionality, wallet interaction components
Acceptance Criteria:

• All user inputs validated using schema-based validation
• XSS protection implemented and tested with OWASP benchmarks
• Wallet addresses validated against blockchain standards
• Rate limiting implemented for all form submissions
• Content Security Policy headers properly configured
• Automated security testing integrated into CI/CD
• Security audit passes with no high-severity vulnerabilities
• Input sanitization prevents injection attacks