feat(游戏共创): 贡献归集纯函数与归因分解（own/inherited/total + 按代际/直接子代明细 + 上限截断）

server-rs/crates/module-game-distribution/src/lib.rs

@@ -1,6 +1,7 @@
 mod application;
 mod collection;
 mod commands;
+mod contribution;
 mod domain;
 mod errors;
 mod events;
@@ -32,6 +33,12 @@ pub use collection::{
 pub use commands::{
     CreateGameInput, CreateVersionInput, IdempotencyRequest, PurchaseGameInput, ReviewDecision,
 };
+pub use contribution::{
+    ContributionBreakdown, ContributionChildBreakdown, ContributionGenerationBreakdown,
+    ContributionNode, ContributionTotals, ContributionTruncationReason,
+    GAME_DISTRIBUTION_CONTRIBUTION_DEPTH_LIMIT, GAME_DISTRIBUTION_CONTRIBUTION_NODE_LIMIT,
+    build_contribution_breakdown,
+};
 pub use domain::{
     FORK_AUTHORIZATION_FORBIDDEN, FORK_AUTHORIZATION_FULL, FORK_AUTHORIZATION_NON_COMMERCIAL,
     ForkAuthorization, GAME_DISTRIBUTION_CHANGE_SUMMARY_MAX_CHARS,