Allow fixed size day cells in Calendar

[angryPodo]

Feature

Currently, Calendar forces day cells to fill the width evenly using Modifier.weight(1f). This makes it difficult to implement designs requiring fixed-size day cells (e.g., small circles with custom spacing), as the touch area and selection background stretch unintentionally.

I propose adding an option to disable this forced weight distribution. Ideally, we could choose between the current "Fill" behavior and a "Fixed" behavior where we can define a specific size (Dp) and arrangement for the days.

Tech (if applicable)

I've checked the implementation in CalendarMonths.kt. We could introduce a configuration interface (e.g., DaySize) with Fill (default) and Fixed options.

If Fixed is selected, we would use Modifier.size(...) instead of weight(1f) and apply the user's Arrangement to the Row.

I am willing to implement this and submit a PR!

[kizitonwose]

You can get the same result by setting the calendar component to the desired day size multiplied by 7. This way, when we use Modifier.weight(1f) in the day cells, then it's your desired size.