fix: valgrind crash for unresolved libpython

[not-matthias]

No description provided.

[not-matthias]

I feel like a shell script might make the logic of finding the dir and creating the symlink a bit more clear. The downside is that we won't have direct insights into what failed. However, we could add some stderr logs which we can show in case of a crash/fail.

@art049 @GuillaumeLagrange wdyt?

[not-matthias]

A few changes:

• Decided to write the logic in bash, which makes it much less verbose and easier to test and develop (can just copy it to a shell script and run it locally).
• Added a message that is always displayed when the script runs successfully (even if no symlink was applied). I feel like it's not worth it to add an extra exit code that determines whether a symlink was created since the symlink won't really cause anything to crash.

(reflex-perf) [15:50] not-matthias:reflex-perf (main)> codspeed run -- pytest tests/benchmarks/ 
Unofficially supported system: nixos 25.05. Continuing with best effort support.

►►► Preparing the environment
Valgrind is already installed with the correct version, skipping installation
Successfully added symlink for libpython in the venv                                             <-- added
Environment ready

• Checking for both uv python find and python3 in the path to make sure we find the right venv.

[art049]

That's nice, yes. It seems better to have this logic in a shell script. Can you include it using include! so we can benefit from syntax highlighting and linting (I use shellcheck locally, for example. We probably don't need to include this lint in CI, though.

[art049]

looks good

[art049]

we might have to refine a bit the way we find the Python executables we need to patch but this will do for now !