修复邀请入群交互：点击邀请要直接进入邀请，而不是先看成员列表再点第二次

用户实测反馈的真实bug：GroupDetailColumn里那个专门的"+邀请"图标（虚线边框
方块，只有canInvite为真才显示——这个权限门控本身一直是对的）点击后走的是
setOpenModal('members')，和"查看全部成员"是完全同一个入口——弹出的是成员
列表，标题栏里那个真正的"邀请"按钮还要再点一次才能看到可邀请的联系人列表。

GroupMembersModal新增initialView属性，"invite"直接以邀请视图打开（跳过
成员列表这一步），"查看全部"/"查看全部成员"两处不受影响仍然打开成员列表。

同时补全了邀请结果的反馈——原来邀请成功后只做了查询失效，无论是"立即加入"
还是需要对方/群设置审批的"待确认"，界面上都没有任何区别于点击前的视觉反馈，
容易让人怀疑是不是点了没反应从而重复点击。读了im_be的serveIMGroupInvitations
源码（不是协议文档的单一示例）确认真实的单人邀请结果有joined/already_member/
pending/pending_approval/failed五种可能，现在每种都有对应的行内文案，
"failed"不计入"已处理"状态，允许原地重试。

实机验证：全新建群后点"+邀请"直接进入邀请视图（标题"邀请成员"，不经过成员
列表）；邀请一个全新好友后确认成功加入、群成员数正确从2变3、界面正确显示
结果反馈。

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/features/groups/GroupDetailColumn.tsx

@@ -81,7 +81,7 @@ export function GroupDetailColumn({ topicId, peerName, onClose, onOpenHistory }:
   const [nicknameEditing, setNicknameEditing] = useState(false);
   const [nicknameDraft, setNicknameDraft] = useState('');
   const [errorToast, setErrorToast] = useState('');
-  const [openModal, setOpenModal] = useState<'members' | 'announcement' | 'files' | 'admin' | 'qrcode' | null>(null);
+  const [openModal, setOpenModal] = useState<'members' | 'invite' | 'announcement' | 'files' | 'admin' | 'qrcode' | null>(null);
   const showError = (err: unknown, fallback: string) => setErrorToast(err instanceof Error ? err.message : fallback);
 
   // Same long-lived-instance leak this exact pattern already caused twice in DetailColumn.tsx --
@@ -284,7 +284,13 @@ export function GroupDetailColumn({ topicId, peerName, onClose, onOpenHistory }:
                 </div>
               ))}
               {canInvite ? (
-                <button type="button" onClick={() => setOpenModal('members')} className="flex flex-col items-center gap-1">
+                // Goes straight to the invite-candidates view (GroupMembersModal's `initialView=
+                // "invite"`), not the member list -- this dedicated "+邀请" tile landing on the member
+                // list and requiring a SECOND click on an in-modal "邀请" button was a real, reported
+                // UX complaint ("点击邀请那个按钮弹出的并不是直接到邀请，而是显示的成员列表，还要再次
+                // 点击邀请"). "查看全部"/"查看全部成员" right below/above this still correctly open the
+                // plain member list -- only THIS tile's whole purpose is inviting.
+                <button type="button" onClick={() => setOpenModal('invite')} className="flex flex-col items-center gap-1">
                   <span className="grid h-11 w-11 place-items-center rounded-lg border border-dashed border-[#c5cad2] text-text-tertiary-3 md:h-10 md:w-10">
                     <Icon name="add" className="text-[18px]" />
                   </span>
@@ -420,8 +426,13 @@ export function GroupDetailColumn({ topicId, peerName, onClose, onOpenHistory }:
 
       <Toast message={errorToast} variant="error" onDone={() => setErrorToast('')} />
 
-      {openModal === 'members' ? (
-        <GroupMembersModal topicId={topicId} canInvite={canInvite} onClose={() => setOpenModal(null)} />
+      {openModal === 'members' || openModal === 'invite' ? (
+        <GroupMembersModal
+          topicId={topicId}
+          canInvite={canInvite}
+          initialView={openModal === 'invite' ? 'invite' : 'members'}
+          onClose={() => setOpenModal(null)}
+        />
       ) : null}
       {openModal === 'announcement' ? (
         <GroupAnnouncementModal topicId={topicId} canEdit={isAdmin} onClose={() => setOpenModal(null)} />