Add File Upload Validation and Security in Upload Module

[grantfox-oss]

Priority: High
Files: src/upload/ directory
Description:

• Implement strict file type validation
• Limit file size to reasonable limits
• Sanitize file names to prevent path traversal attacks
• Store uploaded files in a secure location with proper permissions
• Add support for multiple storage providers (local, S3-compatible, etc.)
  Acceptance Criteria:
• Only allowed file types are accepted
• File size limits are enforced
• File names are sanitized
• No security vulnerabilities in file upload functionality

[dDevAhmed]

I’d like to work on this issue and plan to implement a clean, scalable solution aligned with project's architecture. Happy to collaborate and ship within the expected timeline.

[grantfox-oss]

🦊 GrantFox — @dDevAhmed has been assigned to this issue as part of the Official Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #451)
2. Your PR will be reviewed by the MERIDIAN-CITY maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign campaign!

@dDevAhmed's PR #507 was approved and merged by @Qoder-Undefined.

🏆 @dDevAhmed: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (118 total points). Track your full progress on GrantFox.

👏 Great work, @dDevAhmed! Keep contributing to MERIDIAN-CITY.