feat: add ads/sponsor/captcha modules and polish home & chat UI

frontend/app/chat/ChatShell.tsx

@@ -738,8 +738,7 @@ function CreateGroupModal({
             onChange={(e) => setName(e.target.value)}
             maxLength={32}
             placeholder="2-32 个字符"
-            className="w-full px-3.5 h-10 rounded-lg outline-none"
-            style={{ background: "var(--bg)", border: "1px solid var(--line)", color: "var(--ink)" }}
+            className="field"
           />
         </div>
         <div>
@@ -751,8 +750,7 @@ function CreateGroupModal({
             onChange={(e) => setDescription(e.target.value)}
             maxLength={200}
             rows={3}
-            className="w-full px-3.5 py-2.5 rounded-lg outline-none resize-none"
-            style={{ background: "var(--bg)", border: "1px solid var(--line)", color: "var(--ink)" }}
+            className="field resize-none"
           />
         </div>
         <div>
@@ -796,8 +794,7 @@ function CreateGroupModal({
               value={memberInput}
               onChange={(e) => setMemberInput(e.target.value)}
               placeholder="用户名，多个用空格或逗号分隔"
-              className="w-full px-3.5 h-10 rounded-lg outline-none"
-              style={{ background: "var(--bg)", border: "1px solid var(--line)", color: "var(--ink)" }}
+              className="field"
             />
           </div>
         )}

frontend/app/chat/[id]/ChatRoomClient.tsx

@@ -1856,12 +1856,7 @@ function InvitePanel({
         value={input}
         onChange={(e) => setInput(e.target.value)}
         placeholder="username1, username2"
-        className="w-full px-3.5 h-10 rounded-lg outline-none"
-        style={{
-          background: "var(--bg)",
-          border: "1px solid var(--line)",
-          color: "var(--ink)",
-        }}
+        className="field"
       />
       <button
         onClick={submit}
@@ -1929,12 +1924,7 @@ function SettingsPanel({
           value={name}
           onChange={(e) => setName(e.target.value)}
           maxLength={32}
-          className="w-full px-3.5 h-10 rounded-lg outline-none"
-          style={{
-            background: "var(--bg)",
-            border: "1px solid var(--line)",
-            color: "var(--ink)",
-          }}
+          className="field"
         />
       </div>
       <div>
@@ -1949,12 +1939,7 @@ function SettingsPanel({
           onChange={(e) => setDescription(e.target.value)}
           maxLength={200}
           rows={4}
-          className="w-full px-3.5 py-2.5 rounded-lg outline-none resize-none"
-          style={{
-            background: "var(--bg)",
-            border: "1px solid var(--line)",
-            color: "var(--ink)",
-          }}
+          className="field resize-none"
         />
       </div>
       <button