"Default URL" is percent-encoded in session iframe

[matteosecli]

Describe the bug
When setting the "Default URL" parameter of an "External environment" session launcher to a string containing ? (and possibly other special characters), this is percent-encoded in the session iframe src.

This is an issue because servers such as VS Code accept parameters with /?par1=val1&par2=val2. For example, trying to launch VS Code with a default folder via /?folder=/some/folder results in /%3Ffolder=/some/folder, causing it to fail.

Link to project
https://renkulab.io/p/matteo.secli/nedoqs-tutorials-2026

To Reproduce
Steps to reproduce the behavior:

1. Go to the linked project and copy it
2. Edit the environment of the "Visual Studio Code" session launcher
3. Provide /?folder=/home/jovyan/work as "Default URL"
4. Launch the session
5. You eventually get a "Not found" error in the session iframe
6. Inspect the iframe and change %3F to ? in the src field
7. Now VS Code loads in the desired folder

Expected behavior
"Default URL" parameters should not be percent-encoded.

[matteosecli]

I can confirm this now works for me with Renku 2.14.0.

Thanks a lot! 🎉