fix(model-store): 接受 HF tree API 返回的裸 LFS oid，修复本地模型下载失败 (#1072)

* test(model-store): 复现 HF tree API 返回裸 LFS oid 时模型下载被拒

huggingface.co 与 hf-mirror.com 的 /api/models/{repo}/tree 接口里 lfs.oid
是不带 sha256: 前缀的 64 位十六进制，现有解析只认前缀形式，导致本地模型
下载直接报 unsupported Hugging Face LFS oid。

* fix(model-store): 接受 HF tree API 返回的裸 LFS oid，修复本地模型下载失败

2.0 起 parse_lfs_sha256 只接受 sha256: 前缀，但 huggingface.co 与
hf-mirror.com 的 tree 接口返回的是裸 64 位十六进制，导致下载 Qwen3-ASR
等本地模型时直接报 unsupported Hugging Face LFS oid。改为前缀可选，
仍校验 64 位十六进制。

openless-all/app/crates/openless-core/src/model_store.rs

@@ -2485,10 +2485,10 @@ fn parse_hf_tree_page_for_entry(
     Ok(files)
 }
 
+/// The Hugging Face tree API returns `lfs.oid` as a bare SHA-256 hex digest;
+/// the `sha256:`-prefixed form (as in Git LFS pointer files) is accepted too.
 fn parse_lfs_sha256(oid: &str) -> Result<String, BackendError> {
-    let digest = oid
-        .strip_prefix("sha256:")
-        .ok_or_else(|| invalid("unsupported Hugging Face LFS oid"))?;
+    let digest = oid.strip_prefix("sha256:").unwrap_or(oid);
     if digest.len() != 64 || !digest.bytes().all(|byte| byte.is_ascii_hexdigit()) {
         return Err(invalid("invalid Hugging Face LFS sha256 oid"));
     }
@@ -2940,6 +2940,31 @@ mod tests {
         .is_err());
     }
 
+    #[test]
+    fn hf_tree_accepts_bare_lfs_oid_from_live_api() {
+        // Shape returned by huggingface.co and hf-mirror.com for Qwen/Qwen3-ASR-0.6B
+        // (2026-09-13): `lfs.oid` is the bare hex digest, without a `sha256:` prefix.
+        let entries = vec![serde_json::json!({
+            "type": "file",
+            "oid": "3d4b2a1f0e9c8b7a6d5e4f3a2b1c0d9e8f7a6b5c",
+            "size": 1876091704u64,
+            "path": "model.safetensors",
+            "lfs": {
+                "oid": "79d6cbd4c98c7bbffe9db2edac07f56cd6637d0d5944b27f6c2b8353840323ea",
+                "size": 1876091704u64,
+                "pointerSize": 135
+            }
+        })];
+        let files = parse_hf_tree_page("Qwen/Qwen3-ASR-0.6B", "qwen3-asr-0.6b", &entries).unwrap();
+        assert_eq!(files.len(), 1);
+        assert_eq!(files[0].path, "model.safetensors");
+        assert_eq!(files[0].size_bytes, 1_876_091_704);
+        assert_eq!(
+            files[0].sha256.as_deref(),
+            Some("79d6cbd4c98c7bbffe9db2edac07f56cd6637d0d5944b27f6c2b8353840323ea")
+        );
+    }
+
     #[test]
     fn hf_link_pagination_accepts_same_origin_and_rejects_redirected_origin() {
         let current = "https://huggingface.co/api/models/org/model/tree/main?limit=1000";