LatencyGuard

Add adaptive jitter and diagnostic status command

• Refactors network logic into a dedicated Network.lua module and implements adaptive jitter-aware margin calculation. Adds /latencyguard status command for comprehensive diagnostics. Changes primary slash command from /lg to /latencyguard (with /latguard alias) to avoid conflicts with other addons. Improves landing page UI, adds database value sanitization, and enhances localization with new diagnostic strings.