Week widget

[stratecide]

Type of change(s)

• Bug fix
• Feature / enhancement
• Infrastructure / tooling (CI, build, deps, tests)
• Documentation

What changed and why

• Refactored the existing Weekly Calender Fragment to re-use code in the widget
• Created the week widget

Tests performed

Tested on Pixel 4a emulator with Android 13 and "Small Phone" emulator with Android 16.
Tested the following:

• Create week widget with different color settings
• Checked how the widget looks without and with events (see screenshots)
• Verified that the normal week view also looks correct

Preview

• No Before images since the widget didn't exist before.
• Example 1: no events set

• Example 2: multiple-day event and all-day event shown at the top, multiple events with overlapping timings
• Different colors configured

Closes the following issue(s)

• Closes Week view widget #470

Checklist

• I read the contribution guidelines.
• I manually tested my changes on device/emulator (if applicable).
• I updated the "Unreleased" section in CHANGELOG.md (if applicable).
• I have self-reviewed my pull request (no typos, formatting errors, etc.).
• I understand every change in this pull request.