[TimePicker] Cannot input times during DST transition on time-only formats

[mbechev]

Description

For time-only formats (formats without year/month/day components), the TimePicker should use a safe, non-DST date (like the default date: January 31, 2000) instead of the current system date.

This would allow all valid times (00:00 - 23:59) to be entered regardless of what day the user opens the TimePicker.

Steps To Reproduce

1. Change your computer's date to a DST transition date. For example, 29 March 2026.
2. Create a TimePicker with a time-only format HH:mm
3. In the time input field, try to type 02:00 (or any time between 2:00 AM - 2:59 AM for spring-forward dates). The input will be rejected or invalid because that time doesn't exist on the DST transition date. 02 will be converted to 03 or 3 (depending on the format).

https://stackblitz.com/edit/angular-mfxtnyvz

Actual Behavior

The date for TimePicker is automatically set to the current system date (new Date()) when the user opens the time picker on a day when the clock is moved forward or backward (DST). The user has no control over this—they just want to pick a time, but they're unknowingly affected by what date it is today.

The unexpected time correction also happens on dates outside DST change, for example, 2nd April 2026 — Machine timezone: America/Chicago, and only for TimePicker, which doesn't have an initial date:

https://stackblitz.com/edit/angular-4ttxye3a

Screen.Recording.2026-04-02.at.6.51.56.mov

Expected Behavior

For time-only formats, use a safe default date so that any time can be entered without relying on DST dates.