Add print time tiebreaker to November challenge

Upcoming-Challenge.md

@@ -31,6 +31,7 @@ Can you achieve the smoothest, most layer-line-free surface finish possible? Thi
 1. **Layer Line Visibility** (100%): The appearance and visibility of layer lines - less visible is better
    - All cubes must meet basic challenge requirements (25mm cube dimensions, exactly 2 walls, 0.4mm nozzle, no post-processing)
    - Winner is determined solely by smoothness of surface and minimal layer line appearance
+   - **Tiebreaker**: If two prints are too close to differentiate, the fastest print time wins
 
 ### Submission Requirements
 
@@ -38,6 +39,7 @@ Can you achieve the smoothest, most layer-line-free surface finish possible? Thi
 - **Dimension Verification**: Must be exactly 25mm x 25mm x 25mm
 - **Wall Count Verification**: Must show exactly 2 walls when inspected
 - **Nozzle Verification**: Must be printed with 0.4mm nozzle
+- **Print Time**: Record and report your total print time (used as tiebreaker if needed)
 - **Settings Documentation**: Share your winning settings (layer height, temperature, speed, cooling, techniques)
 - **Process Notes**: Brief description of your approach