feat: upgrade to Common SDK v4 with new interfaces

MIGRATION-NOTES.md

@@ -0,0 +1,73 @@
+# Migration Notes: Android SDK v4 Upgrade
+
+## Current Status
+- **Phase:** Blocked - waiting for common SDK SNAPSHOT publish
+- **Branch:** `feature/v4-core-upgrade/pr3-sdk-v4-upgrade`
+- **PR:** #246 (Draft)
+- **Last Updated:** 2026-02-21
+
+### CI Status: FAILING (Dependency Resolution)
+CI cannot compile because `eppo-sdk-framework:0.1.0-SNAPSHOT` isn't published to Maven Central Snapshots.
+
+**Error:** `cannot find symbol: method execute(EppoConfigurationRequest)`
+
+The tests and code are correct, but CI can't find the `execute()` method because the SNAPSHOT dependency isn't available remotely.
+
+## Blocker
+
+**Action Required:** Publish `eppo-sdk-framework:0.1.0-SNAPSHOT` from the common SDK repository to Maven Central Snapshots.
+
+Once published, CI should pass because:
+1. Jackson deserializers are correctly configured
+2. Mock tests now stub `execute()` (the correct method in v4)
+3. Offline tests already pass
+
+## Recent Fixes
+
+### Fixed: Mock tests calling wrong method (2026-02-21)
+Tests were stubbing `mockHttpClient.get()` but SDK v4's `ConfigurationRequestor` calls `execute()`.
+The `get()` method is now a deprecated default method in `EppoConfigurationClient` that delegates to `execute()`.
+
+Changed all test mocks from:
+```java
+when(mockHttpClient.get(any(EppoConfigurationRequest.class))).thenReturn(response);
+```
+to:
+```java
+when(mockHttpClient.execute(any(EppoConfigurationRequest.class))).thenReturn(response);
+```
+
+### Fixed: Jackson deserializers for v4 configuration
+Added EppoModule and deserializers from common SDK to properly parse v4 flag config.
+
+Files added in `dto/adapters/`:
+- `EppoModule.java`
+- `FlagConfigResponseDeserializer.java`
+- `BanditParametersResponseDeserializer.java`
+- `EppoValueDeserializer.java`
+- `EppoValueSerializer.java`
+- `DateSerializer.java`
+
+## Test Categories
+
+### Expected Passing Tests (after SNAPSHOT is published)
+- `testOfflineInit` - Uses `initialConfiguration(byte[])`
+- `testObfuscatedOfflineInit` - Same with obfuscated config
+- `testLoadConfiguration` - Uses mocked HTTP client
+- `testPollingClient` - Uses mocked HTTP client
+- All other mock-based tests
+- Unit tests (local)
+
+## Commits on Branch
+- `4b9a599` fix: stub execute() instead of get() in mock tests
+- `84b50dd` style: fix import ordering for spotless
+- `5995f89` feat: add Jackson deserializers for v4 configuration parsing
+- `0b45c98` docs: update migration notes with recent fixes
+- Earlier commits for initial v4 upgrade
+
+## Dependency Graph
+```
+Android SDK (eppo module)
+    └── eppo-sdk-framework:0.1.0-SNAPSHOT  <-- NOT PUBLISHED
+            └── Contains: EppoConfigurationClient.execute()
+```

eppo/build.gradle

@@ -68,11 +68,14 @@ ext.versions = [
 ]
 
 dependencies {
-    api 'cloud.eppo:sdk-common-jvm:3.13.1'
+    // Use v4 framework - provides base classes and interfaces
+    api 'cloud.eppo:eppo-sdk-framework:0.1.0-SNAPSHOT'
 
     implementation 'org.slf4j:slf4j-api:2.0.17'
 
     implementation "androidx.core:core:${versions.androidx_core}"
+    // OkHttp and Jackson still needed temporarily in framework
+    // They will be moved to batteries-included in PR 4
     implementation "com.squareup.okhttp3:okhttp:${versions.okhttp}"
     implementation "com.github.zafarkhaja:java-semver:${versions.semver}"
     implementation "com.fasterxml.jackson.core:jackson-databind:2.19.1"