Integration tests: full lobby→game→end lifecycle

Description

Currently only unit tests exist (~70-75% coverage on isolated components). There are no integration tests that exercise the complete game lifecycle end-to-end: players joining lobby → preparation countdown → active race → all players finish → end screen → results persisted.

Acceptance Criteria

• At least one integration test covers the full Lobby → Preparation → Game → End phase sequence
• Test uses Minestom Testing framework (fake server + fake players)
• Verifies: phases transition in order, ring collisions register, scores accumulate, EndPhase fires, DB write is invoked (mocked)
• Test runs in CI (./gradlew :server:test) without needing a live DB
• Coverage report shows integration test path contributes to the overall metrics
• Edge case: single player finishing early while others are still racing

Technical Details

• Integration tests go in server/src/test/java/
• Use MinestomTestEnv from Minestom Testing
• DB interaction should be mocked via Mockito to keep tests self-contained
• Consider a TestCupFixture helper that creates a minimal cup/map with 3 rings

Dependencies

• "Wire database service" must be implemented first (so it can be properly mocked)

Estimate

L

After the “Wire database service” dependency is complete, start in server/src/test/java/ with MinestomTestEnv and review the existing game phase entry points. Build the test around a minimal TestCupFixture with 3 rings, mock database interaction with Mockito, and run ./gradlew :server:test. Done means the full phase sequence, collisions, scores, EndPhase, mocked DB write, early-finishing player case, and coverage contribution are verified in CI.