补充项目内路径形状用例（/ 写法与大小写变体）

- direct_tool_calls.rs：新增单测 tool_call_paths_normalize_separators_and_case，
  覆盖 relativize_project_root_paths 的 `/` 分隔符分支与大小写不敏感分支
  （Codex 上报的路径分隔符与盘符大小写不受我们控制，这两条分支此前没有用例覆盖）

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

@@ -1277,4 +1277,35 @@ mod tests {
             "回读必须按时间正序"
         );
     }
+
+    /// 判据：项目内路径的 `\` / `/` 两种写法与大小写变体都要落成同一份项目相对路径
+    /// （Codex 上报的路径分隔符与盘符大小写不受我们控制）。
+    #[test]
+    fn tool_call_paths_normalize_separators_and_case() {
+        let root = init_tool_call_project("tool-call-path-variants");
+        let native = root.path().to_string_lossy().to_string();
+        let variants = [native.replace('\\', "/"), native.to_ascii_uppercase()];
+        let mut paths = Vec::new();
+        for (index, variant) in variants.into_iter().enumerate() {
+            let call = direct_tool_call_from_item(
+                root.path(),
+                &json!({
+                    "id": format!("item-path-variant-{index}"),
+                    "type": "fileChange",
+                    "changes": [{"path": format!("{variant}/game/src/y.ts"), "kind": "update"}],
+                    "startedAtMs": 1000,
+                }),
+                "turn-1",
+                false,
+                1000,
+            )
+            .expect("variant path tool call");
+            paths.push(call.detail.changes[0].path.clone());
+        }
+        assert_eq!(paths[0], "game/src/y.ts", "`/` 写法同样要落成项目相对路径");
+        assert_eq!(
+            paths[1], "game/src/y.ts",
+            "大小写变体同样要落成项目相对路径"
+        );
+    }
 }