fix(send): keep c2c video compatQMsgSceneType at 2 (#38)

Commit 29f28d6 changed c2c video `compatQmsgSceneType` from 2 to 1
as a "symmetric asymmetry" cleanup, matching the image/ptt convention
where the field tracks the upload's sceneType (c2c=1, group=2). For
video this is wrong.

Image and ptt have *different* legacy compat elements per scene
(notOnlineImage vs customFace; ptt c2c vs group), so the server needs
to know which scene shape to emit. The legacy `videoFile` element
(packet element type 19) has no scene split — fromChatType /
toChatType live inside the element itself — so the QQ NT server
emits a single group-shaped compat payload regardless. NapCat
hardcodes `compatQMsgSceneType: 2` for *both* UploadGroupVideo and
UploadPrivateVideo for exactly this reason.

Setting it to 1 on c2c made the server emit a c2c-scene shaped
compat blob that older QQ clients failed to resolve, showing the
message as "视频已过期" on those receivers. Newer clients only read
the commonElem(48, 11) and displayed fine — which is why only "some
devices" saw the breakage.

Keep `commonElem.businessType = isGroup ? 21 : 11` untouched — that
piece of 29f28d6 is still correct and is what fixed PbSendMsg
result=79.

packages/core/src/bridge/highway/video-upload.ts

@@ -487,11 +487,17 @@ export async function uploadVideoMsgInfo(
           subFileType: 100,
         },
       ],
-      // Scene tag the NTV2 upload registers under. image-upload and
-      // ptt-upload both differentiate (group=2, c2c=1); video was
-      // hardcoded to the group value, which contributed to the c2c
-      // send-back rejection (PbSendMsg result=79).
-      compatQmsgSceneType: isGroup ? 2 : 1,
+      // Hardcoded 2 even on c2c (matches NapCat). Image/PTT use
+      // `isGroup ? 2 : 1` because their legacy compat elements differ
+      // per scene (notOnlineImage vs customFace; ptt c2c vs group),
+      // but the legacy `videoFile` element has no scene split — its
+      // fromChatType/toChatType live inside the element itself — so
+      // the server generates a single group-shaped compat payload
+      // regardless. Setting 1 here makes the server emit a c2c-scene
+      // shaped compat blob that old QQ clients fail to resolve,
+      // showing the message as "视频已过期" on those receivers while
+      // new clients (which only read the commonElem) display fine.
+      compatQmsgSceneType: 2,
       extBizInfo: {
         pic: { bizType: 0, textSummary: 'Nya~' },
         video: { bytesPbReserve: new Uint8Array([0x80, 0x01, 0x00]) },