Fix routing regex and prevent XSS in templates

[jbalagiya]

This commit addresses two critical issues:

1. Updated regex routing paths in worker.js to correctly capture base64 URIs containing slashes, fixing broken link redirections.
2. Implemented escapeForScript helper function and updated renderTemplate to safely escape user input and prevent special string replacement bugs ($&) and XSS vulnerabilities during string .replace().

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PR created automatically by Jules for task 1816325902798483291 started by @jbalagiya

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