fix(service-party-app): remove wallet password input from transfer page

Current system uses empty password for share encryption, so the password
input field is unnecessary and confusing for users.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/mpc-system/services/service-party-app/src/pages/Transfer.module.css

@@ -125,7 +125,7 @@
 .maxButton {
   position: absolute;
   right: var(--spacing-sm);
-  top: 36px;
+  bottom: var(--spacing-sm);
   background: var(--primary-color);
   color: white;
   border: none;
@@ -133,6 +133,11 @@
   padding: var(--spacing-xs) var(--spacing-sm);
   font-size: 12px;
   cursor: pointer;
+  z-index: 1;
+}
+
+.amountInput {
+  padding-right: 60px !important;
 }
 
 .maxButton:hover {

backend/mpc-system/services/service-party-app/src/pages/Transfer.tsx

@@ -41,7 +41,8 @@ export default function Transfer() {
   // 表单输入
   const [toAddress, setToAddress] = useState('');
   const [amount, setAmount] = useState('');
-  const [password, setPassword] = useState('');
+  // 当前系统不使用密码，硬编码为空
+  const password = '';
 
   // 交易信息
   const [txParams, setTxParams] = useState<TransactionParams | null>(null);
@@ -321,15 +322,21 @@ export default function Transfer() {
           <div className={styles.formGroup}>
             <label className={styles.label}>转账金额 (KAVA)</label>
             <input
-              type="number"
-              className={styles.input}
+              type="text"
+              inputMode="decimal"
+              className={`${styles.input} ${styles.amountInput}`}
               placeholder="0.0"
               value={amount}
-              onChange={(e) => setAmount(e.target.value)}
-              step="0.000001"
-              min="0"
+              onChange={(e) => {
+                // 只允许数字和小数点
+                const val = e.target.value;
+                if (val === '' || /^\d*\.?\d*$/.test(val)) {
+                  setAmount(val);
+                }
+              }}
             />
             <button
+              type="button"
               className={styles.maxButton}
               onClick={() => setAmount(share?.balance || '0')}
             >
@@ -337,17 +344,6 @@ export default function Transfer() {
             </button>
           </div>
 
-          <div className={styles.formGroup}>
-            <label className={styles.label}>钱包密码</label>
-            <input
-              type="password"
-              className={styles.input}
-              placeholder="输入密码以解锁钱包"
-              value={password}
-              onChange={(e) => setPassword(e.target.value)}
-            />
-          </div>
-
           {error && <div className={styles.error}>{error}</div>}
 
           <button