Importing scenes not detected

Nobody has claimed this yet.

## Description of bug / unexpected behavior
Importing a scene from one file does not expose it in another file.

## Expected behavior
I have scenes in multiple files. I was hoping to be able to import them into one main module so I had a single entry point into the animations for this project. I would expect manim to detect the scenes in that module but it does not seem to.

## How to reproduce the issue

Code for reproducing the problem

```py
# scene_a.py
from manim import *

class CreateCircle(Scene):
def construct(self):
circle = Circle() # create a circle
circle.set_fill(PINK, opacity=0.5) # set the color and transparency
self.play(Create(circle)) # show the circle on screen
```
```py
# main.py
from scene_a import CreateCircle
```

## Logs
Terminal output

```
manim -v DEBUG main.py
Manim Community v0.19.0

[06/03/25 13:24:15] ERROR module_ops.py:93
There are no scenes inside that module

```

## System specifications

System Details

- OS (with version, e.g., Windows 10 v2004 or macOS 10.15 (Catalina)): Linux 6.12.21 x86_64 GNU/Linux
- Python version (`python/py/python3 --version`): 3.12.9
- Installed modules (provide output from `pip list`):
```
Package Version
-------------------- -----------
annotated-types 0.7.0
asttokens 3.0.0
av 13.1.0
beautifulsoup4 4.12.3
brotlicffi 1.1.0.0
certifi 2024.12.14
cffi 1.17.1
chardet 5.2.0
charset-normalizer 3.4.1
click 8.1.8
click-default-group 1.2.4
cloup 3.0.5
contourpy 1.3.1
cycler 0.12.1
decorator 5.1.1
executing 2.1.0
fonttools 4.55.3
glcontext 3.0.0
idna 3.10
ipython 8.32.0
isosurfaces 0.1.2
jedi 0.19.2
Jinja2 3.1.5
kiwisolver 1.4.8
lxml 5.3.0
manim 0.19.0
manim-slides 5.4.2
ManimPango 0.6.0
mapbox_earcut 1.0.3
markdown-it-py 3.0.0
MarkupSafe 3.0.2
matplotlib 3.10.0
matplotlib-inline 0.1.7
mdurl 0.1.2
moderngl 5.12.0
moderngl-window 3.1.1
networkx 3.4.2
numpy 2.2.3
packaging 24.2
parso 0.8.4
pexpect 4.9.0
pillow 11.1.0
pip 24.0
prompt_toolkit 3.0.48
ptyprocess 0.7.0
pure_eval 0.2.3
pycairo 1.27.0
pycparser 2.22
pydantic 2.10.5
pydantic_core 2.27.2
pydantic-extra-types 2.10.2
pydub 0.25.1
pyglet 2.0.10
PyGLM 2.7.3
Pygments 2.19.1
pyparsing 3.2.1
python-dateutil 2.9.0.post0
python-pptx 1.0.2
QtPy 2.4.3
requests 2.32.3
rich 13.9.4
rtoml 0.10.0
scipy 1.15.2
screeninfo 0.8.1
semver 3.0.3
six 1.17.0
skia-pathops 0.8.0.post2
soupsieve 2.6
srt 3.5.3
stack_data 0.6.3
svgelements 1.9.6
toml 0.10.2
tqdm 4.67.1
traitlets 5.14.3
typing_extensions 4.12.2
urllib3 2.3.0
watchdog 6.0.0
wcwidth 0.2.13
XlsxWriter 3.2.0
```

Start by running `manim -v DEBUG main.py` with the provided `scene_a.py` and `main.py` example, then trace the scene-discovery entry point that reports no scenes. Done means an imported `CreateCircle` is detected and available through the main module without breaking direct scene discovery.

Written by the indexing model from the issue text.