🔒 Fix Potential Shell Command Injection in PDF Conversion Script

[dynamikdev]

🎯 What: Fixed a shell command injection and word-splitting vulnerability in scripts/convert_pdfs.sh due to unsafe echo $num usage and basename/sed subshells.
⚠️ Risk: If an attacker could control the filenames of PDFs or generated images (e.g., adding spaces, globs, or command terminators like ; or $()), it could lead to arbitrary shell command execution, unexpected behavior, or broken script execution (DoS).
🛡️ Solution: Replaced external commands with secure bash parameter expansions (${var##*/}, ${var%pattern}, ${var#pattern}) and properly quoted strings. Also added a check [ -e "$f" ] || continue to handle cases where the glob matches nothing.

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PR created automatically by Jules for task 16531367517710798224 started by @dynamikdev

[google-labs-jules]

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