Config Parser Reader

Write a function `parse_config(text: str) -> dict` that parses a simplified INI-style configuration string into a Python dictionary. **Format rules:** - Lines may contain leading/trailing whitespace, which should be ignored. - Empty lines and lines where the first non-whitespace character is `#` or `;` are comments and should be skipped. - Section headers are on a line starting with `[` and ending with `]` (ignoring surrounding whitespace). The section name is the text between the brackets. The dictionary will have the section name as a key, and its value is a dictionary of the key-value pairs that follow it. - Key-value lines are of the form `key = value` or `key: value`. The separator is the first `=` or `:` that appears (outside of the value). Both key and value are stripped of leading/trailing whitespace. - A key-value line that appears before any section header should be placed under an empty-string section key (`''`). - If a line is otherwise invalid (no separator, malformed section header), ignore it completely. - All keys and values are returned as strings. No type conversion. - Sections may have duplicate keys: the last occurrence wins. - If the same section appears again later, its keys are merged into the existing section dictionary (later keys override earlier keys). Return the resulting dictionary. The order of keys in the dictionary does not matter for the test (we compare as dictionaries).

>>> parse_config("""
... # comment
... key1 = value1
... [section1]
... a = 1
... b: two
... [section2]
... x = y
... """)
{'': {'key1': 'value1'}, 'section1': {'a': '1', 'b': 'two'}, 'section2': {'x': 'y'}}

>>> parse_config("[s]\n k = v \n")
{'s': {'k': 'v'}}

>>> parse_config("")
{}