test(model): add unit tests for AlarmModel (#882)

[dorodb-web22]

Fixes #882

Description

Added a proper unit test file for AlarmModel. noticed while working on some other bugs that the data models don't have any test coverage right now, so i wrote these to lock down the expected behavior.

Proposed Changes

• added 29 tests covering fromMap correctness (including edge cases like maxSnoozeCount defaulting to 3)
• added toMap / fromMap roundtrip tests (especially verifying the mainAlarmTime conditional logic for shared alarms)
• added valid encoding tests for toJson
• added single-day rotation logic tests for boolListToString (verifying the sun-first storage vs mon-first list contract)

Besides, i left out tests for the fromJson constructor intentionally because it's currently broken on main ... there's an open PR #868 to fix that separately).*

Screenshots

n/a (unit tests only)

Checklist

• Tests have been added or updated to cover the changes
• Documentation has been updated to reflect the changes
• Code follows the established coding style guidelines
• All tests are passing