feat: add kotlin-example module using android-sdk-framework directly

[typotter]

Summary

New :kotlin-example Android application module demonstrating how to use :android-sdk-framework directly (without going through :eppo). Written in Kotlin, uses kotlinx.serialization for JSON flag values and OkHttp 4.x for HTTP.

Stacked on snapshot/typo/apr-17.

What's in this PR

New module: :kotlin-example

File	Purpose
KotlinxConfigurationParser	ConfigurationParser<JsonElement> — parseJsonValue uses kotlinx.serialization; parseFlagConfig/parseBanditParams delegated to JacksonConfigurationParser (framework DTOs have hand-rolled Jackson deserializers)
EppoApplication	Wires BaseAndroidClient.Builder with KotlinxConfigurationParser + OkHttpEppoClient in Application.onCreate()
MainActivity	Shows flag assignment result via getStringAssignment()

Changed: CachingConfigurationStore.seedCache() visibility

Made public (was package-private). BaseAndroidClient and CachingConfigurationStore are in different packages so package-private was inaccessible.

Dependency note

Uses sdk-common-jvm:4.0.0-SNAPSHOT not 3.13.1. The old 3.13.1 monolithic jar bundles eppo-sdk-framework classes and produces duplicate class errors when combined with eppo-sdk-framework:0.1.0-SNAPSHOT from :android-sdk-framework.

Resolves #253

[aarsilv]

Nice work proving this out in an example!

[aarsilv]

🔥

[Copilot]

Pull request overview

Adds a new Kotlin sample Android app module (:kotlin-example) that demonstrates using :android-sdk-framework directly (w/ kotlinx.serialization for JSON flag values and OkHttp 4.x for HTTP), and adjusts framework visibility to support this usage.

Changes:

• Add new :kotlin-example Android application module (Kotlin + kotlinx.serialization + OkHttp).
• Wire BaseAndroidClient.Builder using KotlinxConfigurationParser and OkHttpEppoClient.
• Make CachingConfigurationStore.seedCache() public to allow cross-package use from BaseAndroidClient.

Reviewed changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
settings.gradle	Includes the new :kotlin-example module in the build.
build.gradle	Adds Kotlin Android + Kotlin serialization plugins at the root.
android-sdk-framework/src/main/java/cloud/eppo/android/framework/storage/CachingConfigurationStore.java	Makes seedCache() public for use outside the storage package.
kotlin-example/build.gradle	Defines the new app module, dependencies (OkHttp, kotlinx.serialization), and BuildConfig API key wiring.
kotlin-example/src/main/AndroidManifest.xml	Declares the sample app, EppoApplication, and launcher activity.
kotlin-example/src/main/kotlin/cloud/eppo/kotlinexample/EppoApplication.kt	Initializes BaseAndroidClient asynchronously using the framework + OkHttp client.
kotlin-example/src/main/kotlin/cloud/eppo/kotlinexample/MainActivity.kt	Displays a sample string assignment result.
kotlin-example/src/main/kotlin/cloud/eppo/kotlinexample/KotlinxConfigurationParser.kt	Implements ConfigurationParser<JsonElement> using kotlinx.serialization for JSON values.
kotlin-example/src/main/res/layout/activity_main.xml	Basic UI for status + assignment display.
kotlin-example/src/main/res/values/colors.xml	Sample theme colors.
kotlin-example/src/main/res/values/strings.xml	App strings for UI text.
kotlin-example/src/main/res/values/themes.xml	MaterialComponents theme for the sample app.
kotlin-example/proguard-rules.pro	Placeholder ProGuard config for the module.

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[Copilot]

The Gradle script loads local.properties via new FileInputStream(...) but never closes the stream. In long-lived Gradle daemons this can leak file descriptors. Use localPropertiesFile.withInputStream { localProperties.load(it) } (or a try-with-resources equivalent) to ensure the stream is closed.

Suggested change

	localProperties.load(new FileInputStream(localPropertiesFile))
	localPropertiesFile.withInputStream { localProperties.load(it) }

[Copilot]

The thrown ConfigurationParseException message includes the full jsonValue string. This can unintentionally leak sensitive flag payloads into logs/crash reports and can also be very large. Prefer omitting the raw value (or logging a truncated/length-only version) and rely on the cause exception for debugging details.

Suggested change

	throw ConfigurationParseException("Failed to parse JSON value: $jsonValue", e)
	throw ConfigurationParseException(
	"Failed to parse JSON value (length=${jsonValue.length})",
	e,
	)