[CHORE] Improve the default writeup rules

[proditis]

Improve our default writeup rules

Please keep the following points in mind for future writeups:

• Do not include the contents of the actual flags.
• Do not add top H1 heading to the submitted writeups.
• Do not include metadata such as the target's hostname or IP address, as this information is already provided.
• Do not include your author details, as they are already part of the submission.
• Avoid excessive tool output, such as large ASCII art banners (e.g., from RustScan), since they do not add value to the writeup.
• Do not include the source code of challenge files unless it is necessary to explain your findings.
• Most importantly, explain the reasoning behind your approach. Describe how you arrived at each conclusion instead of simply pasting the commands you executed.