取消抠图工具的每回合四项媒体请求限制

resource_request_ids 增加 enforce_turn_limit 参数，上限检查只在付费路径生效

agc_remove_background 传 false 豁免上限，id 派生与幂等复用不变

create_or_derive（含 agc_edit_image 委托）维持四项上限与原有报错文案

决策记录补充 2026-09-18 抠图豁免条目

实施计划文档同步注明抠图不占四项额度

apps/ai-game-creator-shell/src-tauri/src/agent/direct_tool_bridge.rs

@@ -637,7 +637,11 @@ impl DirectToolBridgeState {
         Ok(())
     }
 
-    fn resource_request_ids(&self, request_fingerprint: &str) -> Result<(String, String), String> {
+    fn resource_request_ids(
+        &self,
+        request_fingerprint: &str,
+        enforce_turn_limit: bool,
+    ) -> Result<(String, String), String> {
         let mut authorization = self
             .turn_authorization
             .lock()
@@ -649,7 +653,9 @@ impl DirectToolBridgeState {
         if let Some(ids) = active.resource_request_ids.get(request_fingerprint) {
             return Ok(ids.clone());
         }
-        if active.resource_request_ids.len() >= DIRECT_TOOL_BRIDGE_MAX_RESOURCE_CALLS_PER_TURN {
+        if enforce_turn_limit
+            && active.resource_request_ids.len() >= DIRECT_TOOL_BRIDGE_MAX_RESOURCE_CALLS_PER_TURN
+        {
             return Err("单个用户回合最多只能创建四项媒体资源请求".to_string());
         }
         let operation_id =
@@ -1891,7 +1897,7 @@ async fn bridge_create_or_derive_resource(
             .await?
         } else {
             let (operation_id, idempotency_key) =
-                state.resource_request_ids(&request_fingerprint)?;
+                state.resource_request_ids(&request_fingerprint, true)?;
             let revision = read_game_creator_agent_runtime_project_revision(&state.root)?.revision;
             let source_resource_id = source_asset
                 .as_ref()
@@ -2001,7 +2007,9 @@ async fn bridge_remove_background(state: &DirectToolBridgeState, arguments: &Val
             })
             .await?
         } else {
-            let (operation_id, idempotency_key) = state.resource_request_ids(&fingerprint)?;
+            // 抠图不计费且服务端秒级完成，不占每回合付费媒体请求的四项额度。
+            let (operation_id, idempotency_key) =
+                state.resource_request_ids(&fingerprint, false)?;
             let revision = read_game_creator_agent_runtime_project_revision(&state.root)?.revision;
             let request = DeriveLocalProjectResourceInput {
                 project_path: state.root.to_string_lossy().into_owned(),