修复资产计费边界风险

资产生成预扣费改为 fail-closed，避免钱包异常时继续调用外部生成

新增钱包退款 outbox，退款失败时本地落盘并后台重放

拼图首图后台任务改用 SpacetimeDB claim 表实现跨实例互斥

计费 ledger id 统一绑定 request_id，并让前端重试复用 x-request-id

同步 SpacetimeDB bindings、后端架构文档和 Hermes 决策记录

server-rs/crates/api-server/src/match3d/draft.rs

@@ -162,7 +162,12 @@ pub(super) async fn compile_match3d_draft_for_session(
     let initial_tags = requested_tags
         .clone()
         .unwrap_or_else(|| fallback_work_metadata.tags.clone());
-    let billing_asset_id = format!("{}:{}:{}", session_id, profile_id, current_utc_micros());
+    let billing_asset_id = format!(
+        "{}:{}:{}",
+        session_id,
+        profile_id,
+        request_context.request_id()
+    );
     let points_cost = crate::creation_entry_config::resolve_creation_entry_mud_point_cost(
         state,
         "match3d",
@@ -514,15 +519,6 @@ async fn consume_match3d_draft_generation_points(
         .await
     {
         Ok(_) => Ok(true),
-        Err(error) if should_skip_asset_operation_billing_for_connectivity(&error) => {
-            tracing::warn!(
-                owner_user_id,
-                billing_asset_id,
-                error = %error,
-                "抓大鹅草稿泥点预扣因 SpacetimeDB 连接不可用而降级跳过"
-            );
-            Ok(false)
-        }
         Err(error) => Err(match3d_error_response(
             request_context,
             MATCH3D_AGENT_PROVIDER,