Add test coverage for millisecond support in timeToSeconds

[Copilot]

The timeToSeconds function was enhanced to parse milliseconds (format: HH:MM:SS,mmm and MM:SS,mmm), but the test suite only validated the base HH:MM:SS and MM:SS formats.

Changes:

• Updated test implementation to match actual function signature with comma-separated millisecond parsing
• Added test cases for HH:MM:SS,mmm format: '00:00:00,000', '01:30:45,500', '00:00:01,100', '02:15:30,250'
• Added test cases for MM:SS,mmm format: '00:00,000', '10:00,100', '01:30,500', '05:45,750'
• Fixed parseInt(msPart) → parseInt(msPart, 10) in both source and test to use explicit radix

Example:

timeToSeconds('01:30:45,500')  // 5445.5 seconds
timeToSeconds('10:00,100')     // 600.1 seconds

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