Migrate event sub-row builders

[rfc2822]

This pull request refactors the event-building logic for calendar synchronization by modularizing the mapping of event fields into dedicated builder classes. The main construction logic in LegacyAndroidEventBuilder2 is simplified and extended to use these new builder classes, which improves maintainability and extensibility.

Mapping logic of the fields or tests is not changed.

• Introduced new builder classes (AttendeesBuilder, CategoriesBuilder, DescriptionBuilder, LocationBuilder, RemindersBuilder, RetainedClassificationBuilder, UnknownPropertiesBuilder, UrlBuilder) that each handle mapping a specific aspect of an event to an Android Entity.
• Tests are now unit tests with Roboelectric.

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When this is merged, #71 is the next one.

[Copilot]

Pull Request Overview

This pull request refactors the event-building logic for calendar synchronization by extracting field mapping logic from the monolithic LegacyAndroidEventBuilder2 class into dedicated builder classes. This improves maintainability and extensibility while preserving existing functionality.

Key Changes:

• Extracted field-specific mapping logic into dedicated builder classes (AttendeesBuilder, CategoriesBuilder, DescriptionBuilder, etc.)
• Refactored LegacyAndroidEventBuilder2 to use these modular builders
• Added comprehensive unit tests using Robolectric for the new builder classes

Reviewed Changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
AndroidEntityBuilder.kt	Renamed interface from AndroidEventFieldBuilder to AndroidEntityBuilder and updated documentation
TitleBuilder.kt	Updated to implement the renamed AndroidEntityBuilder interface
AttendeesBuilder.kt	New builder class for mapping event attendees to Android Entity
CategoriesBuilder.kt	New builder class for mapping event categories to extended properties
DescriptionBuilder.kt	New builder class for mapping event description to Android Events field
LocationBuilder.kt	New builder class for mapping event location to Android Events field
RemindersBuilder.kt	New builder class for mapping event alarms/reminders
RetainedClassificationBuilder.kt	New builder class for preserving non-standard classification values
UnknownPropertiesBuilder.kt	New builder class for mapping unknown iCalendar properties
UrlBuilder.kt	New builder class for mapping event URL to extended properties
LegacyAndroidEventBuilder2.kt	Refactored to use new builder classes, removing duplicated mapping logic
Various test files	Added comprehensive unit tests for each new builder class

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[sunkup]

There could be more kdoc on the builder classes for my taste, but we can add than when we look at them in detail :)