feat: 본인 표시이름 자가수정 허용 (계정 설정용)

memberSelfPatch에 displayName 추가 — 유저가 계정 설정에서 표시 이름 변경 가능.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/httpapi/handlers_members.go

@@ -63,6 +63,7 @@ func (s *Server) handleCreateMember(w http.ResponseWriter, r *http.Request) {
 
 // memberSelfPatch is the small set of fields a member may edit on their own row.
 type memberSelfPatch struct {
+	DisplayName *string `json:"displayName"`
 	Phone       *string `json:"phone"`
 	Position    *string `json:"position"`
 }
@@ -104,6 +105,9 @@ func (s *Server) handlePatchMember(w http.ResponseWriter, r *http.Request) {
 			writeError(w, http.StatusBadRequest, err.Error())
 			return
 		}
+		if p.DisplayName != nil {
+			m.DisplayName = *p.DisplayName
+		}
 		if p.Phone != nil {
 			m.Phone = *p.Phone
 		}