Clarify Input Fields on Deadline Creation Form

Issue Description:
The current deadline creation form does not clearly indicate what each input field is for. Users have to rely on placeholder text to determine what information should be entered, which can make the form confusing.

The form should be updated to include clear labels and more descriptive field organization so users can easily understand what information is required for each input without having to guess.

Expected Behavior:
Each input field should have a visible and descriptive label, such as deadline description, date, and time, so users can clearly identify what information belongs in each field.

UI:

Start by locating the deadline creation form and reviewing the existing placeholder-only inputs. Update the form so each input has a visible, descriptive label for the deadline description, date, and time; it is done when users can identify every required value without relying on placeholder text.

Written by the indexing model from the issue text.