Stack Trace Sanitizer

You are given a multi-line string that looks like a Python traceback. Each line may contain file paths that are absolute or relative, like `/home/user/project/module.py`. Your task is to write a function `sanitize_traceback(text: str) -> str` that returns the same text but with every file path replaced by its basename (the part after the last `/`). A file path is defined as a contiguous sequence of non-whitespace characters that contains at least one `/` and at least one letter. Replace the entire path with its basename. All other characters (spaces, punctuation, line breaks) remain unchanged. If a path ends with a colon, comma, or other non-letter character, you must include that character in the basename (i.e., strip only the directory, not trailing delimiters). Paths may use forward slashes only. Assume paths are not quoted and are separated from surrounding text by whitespace or line boundaries. Note that the basename may include quoted filename parts like `"module.py` or `module.py"` — in that case the quotes stay. Also, keep any surrounding quotes (like `"..."`) intact; only the path component inside them is shortened.

>>> sanitize_traceback('File "/home/user/project/module.py", line 3\n    x = 1')
'File "module.py", line 3\n    x = 1'
>>> sanitize_traceback('  File "/usr/lib/python3.9/os.py:123", in foo')
'  File "os.py:123", in foo'
>>> sanitize_traceback('Traceback (most recent call last):\n  File "/home/user/app/main.py", line 5, in <module>')
'Traceback (most recent call last):\n  File "main.py", line 5, in <module>'
>>> sanitize_traceback('No paths here')
'No paths here'