FPS Overlay

FPS Overlay TPS/MSPT Freeze Handling Fix

Fixed an issue where TPS and MSPT would display stale values or drop straight to N/A during a server freeze or severe lag spike, instead of reflecting what was actually happening.

• TPS now decays smoothly toward 0 the longer the server goes without responding, instead of holding the last known value or cutting to N/A
• If the server stays unresponsive for over 30 seconds, the display reverts to N/A (handles disconnects/timeouts correctly)
• Applies to both the OP debug-packet reading and the non-OP fallback
• MSPT still shows N/A during a freeze on both paths, unchanged

Thanks to Sk1ght on CurseForge for the bug report that led to this fix.