Fix critical issues in backend auto-updater system

[msanlli]

Summary

The backend auto-updater has critical cross-platform compatibility and security issues. Currently disabled in backend/cmd/main.go:90.

Critical Issues

• Cross-platform: Uses Windows-specific commands (tasklist/taskkill), hard-coded .exe extensions
• Security: No signature/checksum verification of downloaded binaries
• Reliability: Race conditions, no error handling, no rollback mechanism
• Production: Blocking user prompts unsuitable for automated deployments

Current Implementation

• backend/cmd/main.go:668-766 - Update logic
• updater/main.go - Platform-specific updater
• Checks GitHub releases API, prompts user, downloads/replaces binary

Required Fixes

1. Replace Windows-specific process management with cross-platform Go stdlib
2. Add cryptographic verification of downloaded binaries
3. Implement proper error handling and rollback capability
4. Add configuration for automated vs interactive modes
5. Fix release artifact naming consistency

Files

• backend/cmd/main.go (update logic commented out)
• updater/main.go (main implementation)
• .github/workflows/release.yaml (packaging)