fix(tsconnect): lowercase name/size in waitingFiles JSON

apitype.WaitingFile has no json tags so it serialised as {Name, Size}.
Introduce a local jsWaitingFile struct with json:"name" / json:"size"
so the JS side receives idiomatic camelCase property names.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cmd/tsconnect/wasm/taildrop.go

@@ -166,10 +166,15 @@ func (i *jsIPN) waitingFiles() js.Value {
 		if err != nil {
 			return nil, err
 		}
-		if wfs == nil {
-			wfs = []apitype.WaitingFile{}
+		type jsWaitingFile struct {
+			Name string `json:"name"`
+			Size int64  `json:"size"`
 		}
-		b, err := json.Marshal(wfs)
+		out := make([]jsWaitingFile, len(wfs))
+		for i, wf := range wfs {
+			out[i] = jsWaitingFile{Name: wf.Name, Size: wf.Size}
+		}
+		b, err := json.Marshal(out)
 		if err != nil {
 			return nil, err
 		}