Implement __matmul__, typehint pd.DataFrame.eval inplace and test conversion for test_frame.py

[loicdiridollou]

Describe the bug

• @ operator on dataframe is not typehinted properly.
• df.eval("...", inplace=True) returns Unknown
• Convert test for types into check/assert_type framework

To Reproduce

import pandas as pd

df1 = pd.DataFrame([[0, 1, -2, -1], [1, 1, 1, 1]])
df2 = pd.DataFrame([[0, 1], [1, 2], [-1, -1], [2, 0]])

check(assert_type(df1 @ df2, pd.DataFrame ),pd.DataFrame )
check(assert_type(df1.eval("c = 0 + 1", inplace=True), None), type(None))

Please complete the following information:

• OS: [e.g. Windows, Linux, MacOS] MacOS
• OS Version [e.g. 22] 15
• python version 3.12
• version of type checker 1.13
• version of installed pandas-stubs 2.2.3.20241009