feat: Complete Assets module STJ migration (v1.0.0-beta.4)

[OMpawar-21]

Summary

This PR migrates the Assets module from Newtonsoft.Json to System.Text.Json, improving performance and reducing dependencies.

Changes Made

Models Updated

• Updated Asset, Folder, and Version models to use System.Text.Json
• Maintained backward compatibility for existing API consumers

Services Migrated

• Migrated asset upload, folder management, and versioning services
• Replaced legacy JSON serialization with modern STJ APIs
• Updated service constructors to use JsonSerializerOptions

Performance Improvements

• Reduced memory allocation during JSON operations
• Improved serialization performance for asset operations
• Streamlined JSON writing with Utf8JsonWriter

Technical Details

• All asset-related services now use System.Text.Json
• Service constructors updated to accept JsonSerializerOptions
• JSON writing operations migrated to Utf8JsonWriter
• Zero breaking changes to public API

Testing

• All builds pass successfully
• Asset operations function correctly
• No regressions in existing functionality

Breaking Changes

None. This is an internal refactoring that maintains full API compatibility.

Benefits

• Improved JSON serialization performance
• Reduced package dependencies
• Better alignment with .NET ecosystem standards
• Enhanced memory efficiency for asset operations

[github-actions]

🔒 Security Scan Results

ℹ️ Note: Only vulnerabilities with available fixes (upgrades or patches) are counted toward thresholds.

Check Type	Count (with fixes)	Without fixes	Threshold	Result
🔴 Critical Severity	0	0	10	✅ Passed
🟠 High Severity	0	0	25	✅ Passed
🟡 Medium Severity	0	0	500	✅ Passed
🔵 Low Severity	0	0	1000	✅ Passed

⏱️ SLA Breach Summary

✅ No SLA breaches detected. All vulnerabilities are within acceptable time thresholds.

Severity	Breaches (with fixes)	Breaches (no fixes)	SLA Threshold (with/no fixes)	Status
🔴 Critical	0	0	15 / 30 days	✅ Passed
🟠 High	0	0	30 / 120 days	✅ Passed
🟡 Medium	0	0	90 / 365 days	✅ Passed
🔵 Low	0	0	180 / 365 days	✅ Passed

✅ BUILD PASSED - All security checks passed

[github-actions]

🔒 Security Scan Results

ℹ️ Note: Only vulnerabilities with available fixes (upgrades or patches) are counted toward thresholds.

Check Type	Count (with fixes)	Without fixes	Threshold	Result
🔴 Critical Severity	0	0	10	✅ Passed
🟠 High Severity	0	0	25	✅ Passed
🟡 Medium Severity	0	0	500	✅ Passed
🔵 Low Severity	0	0	1000	✅ Passed

⏱️ SLA Breach Summary

✅ No SLA breaches detected. All vulnerabilities are within acceptable time thresholds.

Severity	Breaches (with fixes)	Breaches (no fixes)	SLA Threshold (with/no fixes)	Status
🔴 Critical	0	0	15 / 30 days	✅ Passed
🟠 High	0	0	30 / 120 days	✅ Passed
🟡 Medium	0	0	90 / 365 days	✅ Passed
🔵 Low	0	0	180 / 365 days	✅ Passed

✅ BUILD PASSED - All security checks passed

[sunil-lakshman]

LGTM