AGC 作者预览切到 owner 媒体读路由

- resolve_preview_url 改走 /api/game-distribution/my-games/{gameId}/media/read-url，不再走素材库 /api/assets/read-url
- 新增 owner_media_read_url，复用 endpoint 的路径段转义并编码 objectKey
- 新增路由与编码单测，钉住不再回退素材库 ACL

apps/ai-game-creator-shell/src-tauri/src/game_distribution_publish.rs

@@ -585,11 +585,27 @@ fn clear_publication_binding(root: &Path) {
     });
 }
 
-fn asset_read_url(api_base_url: &str, object_key: &str) -> Result<String, String> {
-    let mut url = Url::parse(&format!(
-        "{}/api/assets/read-url",
-        api_base_url.trim_end_matches('/')
-    ))
+/// owner 作用域媒体读地址：`/api/game-distribution/my-games/{gameId}/media/read-url`。
+///
+/// 不能再走 `/api/assets/read-url`：发布媒体是项目快照桶对象、不建 `asset_object`，素材库 ACL
+/// 不会给它授权；owner 路由按「objectKey 命中调用者自己作品当前行的媒体」放行，未发布 / 被驳回
+/// 的封面与截图也能预览。
+fn owner_media_read_url(
+    snapshot: &PlatformSessionSnapshot,
+    game_id: &str,
+    object_key: &str,
+) -> Result<String, String> {
+    let mut url = Url::parse(&endpoint(
+        snapshot,
+        &[
+            "api",
+            "game-distribution",
+            "my-games",
+            game_id,
+            "media",
+            "read-url",
+        ],
+    )?)
     .map_err(|_| "陶泥儿服务地址无效".to_string())?;
     url.query_pairs_mut().append_pair("objectKey", object_key);
     Ok(url.to_string())
@@ -599,13 +615,14 @@ fn asset_read_url(api_base_url: &str, object_key: &str) -> Result<String, String
 async fn resolve_preview_url(
     client: &reqwest::Client,
     snapshot: &PlatformSessionSnapshot,
+    game_id: &str,
     object_key: Option<&str>,
 ) -> Option<String> {
     let object_key = object_key?.trim();
     if object_key.is_empty() {
         return None;
     }
-    let read_url = asset_read_url(&snapshot.api_base_url, object_key).ok()?;
+    let read_url = owner_media_read_url(snapshot, game_id, object_key).ok()?;
     match crate::assets::resolve_external_asset_signed_url(
         client,
         snapshot.access_token.as_str(),
@@ -797,7 +814,13 @@ async fn build_publication_draft(
     let cover = if cover_asset_id.is_some() || cover_object_key.is_some() {
         Some(GameDistributionPublicationImageDraft {
             asset_id: normalize_asset_id(cover_asset_id),
-            preview_url: resolve_preview_url(client, snapshot, cover_object_key.as_deref()).await,
+            preview_url: resolve_preview_url(
+                client,
+                snapshot,
+                entry.id.as_str(),
+                cover_object_key.as_deref(),
+            )
+            .await,
         })
     } else {
         None
@@ -806,7 +829,13 @@ async fn build_publication_draft(
     for (asset_id, object_key) in screenshots {
         screenshot_drafts.push(GameDistributionPublicationImageDraft {
             asset_id: normalize_asset_id(asset_id),
-            preview_url: resolve_preview_url(client, snapshot, object_key.as_deref()).await,
+            preview_url: resolve_preview_url(
+                client,
+                snapshot,
+                entry.id.as_str(),
+                object_key.as_deref(),
+            )
+            .await,
         });
     }
     GameDistributionPublicationDraft {
@@ -1499,6 +1528,33 @@ mod tests {
         assert!(endpoint(&snapshot, &["api", "bad?query"]).is_err());
     }
 
+    #[test]
+    fn owner_media_read_url_targets_owner_route_and_encodes_object_key() {
+        let snapshot = PlatformSessionSnapshot {
+            user_id: "user-1".to_string(),
+            access_token: "token".to_string(),
+            api_base_url: "https://dev.genarrative.world".to_string(),
+            identity_generation: 1,
+            revision: 1,
+        };
+        let url = owner_media_read_url(
+            &snapshot,
+            "game-1",
+            "agc/project-snapshots/v1/game-distribution/media/game-1/cover-1.png",
+        )
+        .expect("owner media read url");
+        assert!(url.starts_with(
+            "https://dev.genarrative.world/api/game-distribution/my-games/game-1/media/read-url?"
+        ));
+        assert!(
+            url.contains("objectKey=agc%2Fproject-snapshots%2Fv1%2F"),
+            "objectKey 必须按查询参数编码：{url}"
+        );
+        // 作者预览不再回退到素材库 ACL 路由：发布媒体不是 asset_object。
+        assert!(!url.contains("/api/assets/read-url"));
+        assert!(owner_media_read_url(&snapshot, "bad/id", "cover.png").is_err());
+    }
+
     #[test]
     fn response_data_unwraps_v1_envelope_and_legacy_payload() {
         assert_eq!(