Multithreading with PythonCall and PythonPlot leads to a EXCEPTION_ACCESS_VIOLATION

**Affects:** PythonCall

**Bug description**
Having both `PythonCall` and `PythonPlot` imported leads to a `EXCEPTION_ACCESS_VIOLATION` when used with multithreading with an unlocked GIL.

**MWE**
File: src\\Pythoncall_testing.jl
```
import PythonCall
import PythonPlot

PythonCall.GIL.@unlock Threads.@threads for i in 1:5
println("Hello world")
end
```

Commands

Command line:
```
C:\Users\kuhrmann\CODE\pythoncall_testing>julia -t 10
] activate .
include("src\\Pythoncall_testing.jl")
```

Output

```
C:\Users\kuhrmann\CODE\pythoncall_testing>julia -t 10
_
_ _ _(_)_ | Documentation: https://docs.julialang.org
(_) | (_) (_) |
_ _ _| |_ __ _ | Type "?" for help, "]?" for Pkg help.
| | | | | | |/ _` | |
| | |_| | | | (_| | | Version 1.12.5 (2026-02-09)
_/ |\__'_|_|_|\__'_| | Official https://julialang.org release
|__/ |

(@v1.12) pkg> activate .
Activating project at `C:\Users\kuhrmann\CODE\pythoncall_testing`

julia> include("src\\Pythoncall_testing.jl")
Hello world
Hello world
Hello world
Hello world
Hello world

Please submit a bug report with steps to reproduce this fault, and any error messages that follow (in their entirety). Thanks.
Exception: EXCEPTION_ACCESS_VIOLATION at 0x7ffbe8a26c09 -- PyType_GenericAlloc at C:\Users\kuhrmann\CODE\pythoncall_testing\.CondaPkg\.pixi\envs\default\python314.dll (unknown line)
in expression starting at C:\Users\kuhrmann\CODE\pythoncall_testing\src\Pythoncall_testing.jl:4
PyType_GenericAlloc at C:\Users\kuhrmann\CODE\pythoncall_testing\.CondaPkg\.pixi\envs\default\python314.dll (unknown line)
PyUnicode_DecodeUTF8Stateful at C:\Users\kuhrmann\CODE\pythoncall_testing\.CondaPkg\.pixi\envs\default\python314.dll (unknown line)
PyUnicode_DecodeUTF8Stateful at C:\Users\kuhrmann\CODE\pythoncall_testing\.CondaPkg\.pixi\envs\default\python314.dll (unknown line)
PyUnicode_DecodeUTF8 at C:\Users\kuhrmann\.julia\packages\PythonCall\83z4q\src\C\pointers.jl:300 [inlined]
pystr_fromUTF8 at C:\Users\kuhrmann\.julia\packages\PythonCall\83z4q\src\Core\builtins.jl:554
pystr_fromUTF8 at C:\Users\kuhrmann\.julia\packages\PythonCall\83z4q\src\Core\builtins.jl:555 [inlined]
pystr at C:\Users\kuhrmann\.julia\packages\PythonCall\83z4q\src\Core\builtins.jl:563 [inlined]
Py at C:\Users\kuhrmann\.julia\packages\PythonCall\83z4q\src\Core\Py.jl:125 [inlined]
macro expansion at C:\Users\kuhrmann\.julia\packages\PythonCall\83z4q\src\Core\Py.jl:117 [inlined]
pygetattr at C:\Users\kuhrmann\.julia\packages\PythonCall\83z4q\src\Core\builtins.jl:58
getproperty at C:\Users\kuhrmann\.julia\packages\PythonCall\83z4q\src\Core\Py.jl:275 [inlined]
#Tk_eventloop##0 at C:\Users\kuhrmann\.julia\packages\PythonPlot\oS8x4\src\pygui.jl:198
#634 at .\asyncevent.jl:361
unknown function (ip: 000001ead8510a6b) at (unknown file)
jl_apply at C:/workdir/src\julia.h:2391 [inlined]
start_task at C:/workdir/src\task.c:1252
Allocations: 3660481 (Pool: 3660333; Big: 148); GC: 5

C:\Users\kuhrmann\CODE\pythoncall_testing>
```

System info

**Your system**
Please provide detailed information about your system:
- The operating system: Win 11
- The version of Julia, Python, PythonCall, JuliaCall and any other affected packages
- If an issue with PythonCall, the output of `Base.versioninfo()`, `Pkg.status()` and `CondaPkg.status()`.

versioninfo()
```
Julia Version 1.12.5
Commit 5fe89b8ddc (2026-02-09 16:05 UTC)
Build Info:
Official https://julialang.org release
Platform Info:
OS: Windows (x86_64-w64-mingw32)
CPU: 20 × 13th Gen Intel(R) Core(TM) i7-1370P
WORD_SIZE: 64
LLVM: libLLVM-18.1.7 (ORCJIT, alderlake)
GC: Built with stock GC
Threads: 10 default, 1 interactive, 10 GC (on 20 virtual cores)
```

Pkg.status()
```
Project Pythoncall_testing v0.1.0
Status `C:\Users\kuhrmann\CODE\pythoncall_testing\Project.toml`
[6099a3de] PythonCall v0.9.31
[274fc56d] PythonPlot v1.0.6
```

CondaPkg.status()
```
CondaPkg Status C:\Users\kuhrmann\CODE\pythoncall_testing\CondaPkg.toml (empty)
Environment
C:\Users\kuhrmann\CODE\pythoncall_testing\.CondaPkg\.pixi\envs\default
```

**Additional context**
I dont want to use multithreading to plot on many threads, I just have a julia project in which I do multithreaded computation involving python, and the results of which I would like to plot with matplotlib.

From the stacktrace, it seems as though `PythonPlot.__init__()` gets called by each thread, which in turn calls python.
I belive this leads to a crash as the GIL is unlocked (`PythonCall.GIL@unlock`) but was not locked before the `PythonPlot.__init__()`.

This is quite frustrating, as I need both `PythonCall` and `PythonPlot` and I would like to not have to separate them at the project level.

Is there some way to avoid this? Perhaps I can somehow make sure the the `PythonPlot.__init__()` calls are wrapped with `PythonCall.GIL.@lock`?

Let me know if something is unclear!
Thanks for the convenient package otherwise!

Start with src\\Pythoncall_testing.jl and reproduce the crash using Julia 1.12.5, PythonCall 0.9.31, PythonPlot 1.0.6, Windows, and 10 threads. Read the stack trace around PythonPlot's __init__ and pyGui.jl line 198, together with PythonCall.GIL.@unlock. Done means the interaction is understood and the reported access violation no longer occurs in the minimal example.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.