_UPLOAD_SENTENCE_RE word boundary \b prevents /mnt/ path matching

Description

DeerFlow's `_UPLOAD_SENTENCE_RE` regex uses `\b` (word boundary) before `/mnt/`. A `\b` assertion fails before a `/` character because `/` is not a word character boundary. Paths starting with `/mnt/user-data/uploads/` never match the intended pattern.

Reproduction

import re
pattern = re.compile(r'\b/mnt/user-data/uploads/')
bool(pattern.search('/mnt/user-data/uploads/file.txt'))  # False — \b fails before /