Resolve the page UI language once and let each ExApp fill its own Phrases.

Co-authored-by: Cursor <cursoragent@cursor.com>

ocs.go

@@ -10,9 +10,12 @@ import (
 )
 
 // OCSClient performs AppAPI-authenticated OCS requests with format=json.
+// Header is copied onto the outbound request after the AppAPI auth headers.
+// The UI language read uses it to forward Accept-Language.
 type OCSClient struct {
 	Cred   Credentials
 	Client *http.Client
+	Header http.Header
 }
 
 func (c OCSClient) httpClient() *http.Client {
@@ -48,6 +51,11 @@ func (c OCSClient) Call(method, path string, body []byte) ([]byte, error) {
 			req.Header.Set(k, v)
 		}
 	}
+	for k, vs := range c.Header {
+		for _, v := range vs {
+			req.Header.Add(k, v)
+		}
+	}
 	res, err := c.httpClient().Do(req)
 	if err != nil {
 		return nil, err