The `@Deprecated` annotation has been updated to the Kotlin syntax and now includes a `ReplaceWith` expression to provide IDE quick-fix support.

Additionally, new unit tests using Google Truth have been added for the `Point` class to verify its construction and inheritance.

This commit migrates the `Gradient` and `WeightedLatLng` classes and their corresponding tests from Java to idiomatic Kotlin.

This conversion is part of the larger effort to modernize the library and prepare it for Kotlin Multiplatform (KMP) compatibility.

Key changes include:
- `WeightedLatLng` is now a `data class` with a private primary constructor to ensure correct instantiation while providing the benefits of auto-generated methods. The `@ExposedCopyVisibility` annotation has been added to maintain binary compatibility for the `copy()` method.
- `Gradient` has been converted to a Kotlin class, using `@JvmOverloads` for constructor compatibility and a `companion object` for its static helper method.
- The `internal` visibility of a method in `Gradient` was changed to `public` to ensure visibility to Java classes during the mixed-language phase of the migration.
- Unit tests for both classes have been ported to Kotlin, using the Truth assertion framework.

This commit completes the migration of the `heatmaps` package to Kotlin by porting the final and most complex class, `HeatmapTileProvider`.

This conversion modernizes the class by introducing several idiomatic Kotlin features and improves its design by refactoring a key data structure.

Key changes include:
- The `HeatmapTileProvider` and its `Builder` are now written in Kotlin.
- The `getMaxValue()` method was refactored to use a `Map` with a type-safe `Vector` key instead of the Android-specific `LongSparseArray`, improving readability and moving closer to KMP compatibility.
- A new test suite was created from scratch for the provider, as none existed previously. This improves the code coverage and reliability of the module.
- Necessary adjustments were made to the demo application to support the newly ported Kotlin class.

Updates the copyright headers in the test files that were created
during the Kotlin porting process.

- Corrects the copyright year to 2025.
- Corrects the company name from "Google Inc." to "Google LLC".

Updates the copyright headers in the `heatmaps` package source and test files.

- Corrects the copyright year to 2025.
- Corrects the company name from "Google Inc." to "Google LLC".

This commit implements edge-to-edge UI for the demo application.

Changes include:
- Updating the app theme to be edge-to-edge.
- Applying window insets to the base and main activities.
- Adding a separate styles.xml for API 27+ to handle display cutouts.

This commit updates the copyright headers in the following files:
- demo/build.gradle.kts
- demo/src/main/java/com/google/maps/android/utils/demo/BaseDemoActivity.java
- demo/src/main/java/com/google/maps/android/utils/demo/MainActivity.java
- demo/src/main/res/values/styles.xml
- demo/src/main/res/values-v27/styles.xml

….Builder

This commit replaces the `check` function with `require` for validating input data in the `HeatmapTileProvider.Builder`.

Using `require` is more idiomatic for precondition checks, throwing an `IllegalArgumentException` which is more appropriate in this context than the `IllegalStateException` thrown by `check`.

This commit updates `HeatmapTileProviderTest` to expect an `IllegalArgumentException` instead of `IllegalStateException` when building a provider with no data. It also cleans up unused exception variables in catch blocks.