improvement(sns): 精简朋友圈媒体链路并移除手动挑图入口

- 移除 Server-Timing/X-SNS 阶段透出与前端媒体来源标记
- 移除本地候选图与手动匹配接口及预览交互
- /api/sns/media 默认仅保留远程下载解密路径，未命中直接返回 404
- 将导出所需的本地缓存匹配逻辑下沉到 sns_export_service

tests/test_sns_media_route_weflow_default.py

@@ -0,0 +1,39 @@
+import asyncio
+import sys
+import unittest
+from pathlib import Path
+from tempfile import TemporaryDirectory
+from unittest import mock
+
+
+ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(ROOT / "src"))
+
+
+from wechat_decrypt_tool.routers import sns  # noqa: E402  pylint: disable=wrong-import-position
+
+
+class TestSnsMediaRouteWeFlowDefault(unittest.TestCase):
+    def test_route_stops_after_remote_miss_by_default(self):
+        with TemporaryDirectory() as td:
+            account_dir = Path(td) / "acc"
+            account_dir.mkdir(parents=True, exist_ok=True)
+
+            with mock.patch("wechat_decrypt_tool.routers.sns._resolve_account_dir", return_value=account_dir):
+                with mock.patch("wechat_decrypt_tool.routers.sns._try_fetch_and_decrypt_sns_remote", return_value=None):
+                    with self.assertRaises(sns.HTTPException) as ctx:
+                        asyncio.run(
+                            sns.get_sns_media(
+                                account="acc",
+                                url="https://mmsns.qpic.cn/sns/test/0",
+                                key="123",
+                                token="tkn",
+                                use_cache=1,
+                            )
+                        )
+
+        self.assertEqual(ctx.exception.status_code, 404)
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_sns_stage_server_timing.py

@@ -1,40 +0,0 @@
-import sys
-import unittest
-from pathlib import Path
-
-from starlette.responses import Response
-
-
-ROOT = Path(__file__).resolve().parents[1]
-sys.path.insert(0, str(ROOT / "src"))
-
-
-from wechat_decrypt_tool.sns_stage_timing import add_sns_stage_timing_headers  # noqa: E402  pylint: disable=wrong-import-position
-
-
-class TestSnsStageServerTiming(unittest.TestCase):
-    def test_injects_server_timing_when_missing(self):
-        resp = Response(content=b"ok")
-        add_sns_stage_timing_headers(resp.headers, source="proxy")
-        st = str(resp.headers.get("Server-Timing") or "")
-        self.assertIn("sns_source_", st)
-        self.assertIn("proxy", st)
-
-    def test_appends_when_upstream_server_timing_exists(self):
-        resp = Response(content=b"ok")
-        resp.headers["Server-Timing"] = "edge;dur=1"
-        add_sns_stage_timing_headers(resp.headers, source="proxy")
-        st = str(resp.headers.get("Server-Timing") or "")
-        self.assertIn("edge;dur=1", st)
-        self.assertIn("sns_source_", st)
-
-    def test_does_not_duplicate_existing_sns_source_metric(self):
-        resp = Response(content=b"ok")
-        resp.headers["Server-Timing"] = 'sns_source_proxy;dur=0;desc="proxy"'
-        add_sns_stage_timing_headers(resp.headers, source="proxy")
-        st = str(resp.headers.get("Server-Timing") or "")
-        self.assertEqual(st.count("sns_source_"), 1)
-
-
-if __name__ == "__main__":
-    unittest.main()