🔒 fix: prevent sudo option injection in mmdc script

[MiguelRodo]

🎯 What: Fixed a potential option injection vulnerability in src/mermaid/cmd/mmdc when executing sudo.
⚠️ Risk: If a user managed to pass options starting with - to the script, they could potentially inject arguments into the sudo command itself, potentially leading to unauthorized privilege escalation or unexpected behavior.
🛡️ Solution: Added the -- end-of-options delimiter to the sudo call (sudo -u "$USERNAME" -- mmdc ...), forcing sudo to treat all subsequent arguments as the command to execute, neutralizing the option injection vector.

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PR created automatically by Jules for task 5765281476970171348 started by @MiguelRodo

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