Extension of Level-8: Intelligent Date Inference

[W1ndB10w]

Extension of Level-8: Intelligent Date Inference

This PR implements intelligent date inference for Deadline and Event tasks when users provide only time without specifying a date.

Changes Made

1. Deadline Feature Enhancement

• When /by contains only time (e.g., 1800, 6:00 PM), the system now defaults to today's date
• Example: deadline submit report /by 1800 → deadline set to 18:00 today

2. Event Feature Enhancement

Implemented smart date inference logic for events when one field has date+time and the other has only time:

Case A: /from has date+time, /to has only time

• If to_time ≥ from_time: Uses same date as /from
  • Example: event meeting /from 2020-02-28 1700 /to 1900 → Feb 28 17:00 to Feb 28 19:00
• If to_time < from_time: Uses next day
  • Example: event meeting /from 2020-02-28 1700 /to 0200 → Feb 28 17:00 to Feb 29 02:00

Case B: /from has only time, /to has date+time

• If from_time ≤ to_time: Uses same date as /to
  • Example: event meeting /from 1400 /to 2020-03-01 1700 → Mar 01 14:00 to Mar 01 17:00
• If from_time > to_time: Uses previous day
  • Example: event meeting /from 2000 /to 2020-03-01 1700 → Feb 29 20:00 to Mar 01 17:00

3. DateTimeParser Enhancement

• Added case-insensitive AM/PM parsing
• Now accepts: am, AM, pm, PM, Am, Pm, etc.
• Input normalization for consistent parsing