fix(devcontainer): mark workspace as safe dir

[llamantino]

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• [ ] Include this change in the Release Notes. If checked, you must provide an end-user friendly description for your change below

End-user friendly description of the problem this fixes or functionality this introduces.

Prevents Git dubious ownership errors in containers due to ownership mismatch on mounted project folders (more likely on Windows/WSL2).

Fixes issue #5529

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Summarize what the PR does, explaining any non-trivial design decisions.

Adds the repo to git's safe.directory to avoid ownership errors in Dev Containers.

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Link of any specific issues this addresses: