[Bug]: FinalMask configuration breaks on stable Xray-core due to plural schema (Delays/Lengths vs Delay/Length) #845

Before you submit

• I searched existing issues and did not find the same problem.
• I am using the latest available PasarGuard version, or I included the exact version below.

PasarGuard version

5.2.1

Installation type

Docker Compose

What happened?

The panel currently generates FinalMask configuration using plural parameter names (Delays and Lengths).

While this change aligns with newer pre-release Xray-core updates, the official stable/latest Xray-core release (such as v26.3.27) still requires singular parameter names (Delay and Length). As a result, users running the stable latest core experience config rejection or parsing failures when enabling FinalMask.

To ensure smooth operation across all deployments, the panel should support both schemas—either by dynamically checking the running Xray-core version or providing compatibility for both singular and plural parameter definitions.

Steps to reproduce

1. Ensure the panel is running with the stable/latest Xray-core release (e.g., v26.3.27).
2. Go to Host / Inbound settings in the panel UI.
3. Enable FinalMask settings and fill in the values for Delays/Lengths.
4. Save the configuration and restart or check the generated Xray JSON config.
5. Observe config rejection or parsing error by Xray-core due to Delays/Lengths vs Delay/Length schema mismatch.

Expected behavior

The panel should generate FinalMask parameters compatible with both stable/latest and pre-release Xray-core versions (supporting both Delay/Length and Delays/Lengths). The inbound config should parse successfully on stable cores without throwing LengthMin can't be 0 errors.

Logs and error messages

infra/conf: failed to build mask with type fragment > infra/conf: LengthMin can't be 0

Environment

OS: ubuntu24
Database: MySQL
Python version: -
Node.js version: -
Browser: -
Reverse proxy / CDN: -

Relevant configuration

Screenshots or videos

No response

Additional context

No response