feat: update residence learning flows

Commit non-media application and asset changes while leaving audio, video, and environment files out of version control.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/letter/LetterTemplate.tsx

@@ -8,9 +8,9 @@ import { showHint } from '@/components/hint'
 const formatCurrentDate = () => {
   const now = new Date()
   const year = now.getFullYear()
-  const month = `${now.getMonth() + 1}`.padStart(2, '0')
-  const day = `${now.getDate()}`.padStart(2, '0')
-  return `${year}.${month}.${day}`
+  const month = now.getMonth() + 1
+  const day = now.getDate()
+  return `${year}年${month}月${day}日`
 }
 
 export type LetterFieldType = 'text' | 'input' | 'select'
@@ -305,12 +305,14 @@ const LetterTemplate = ({
     }
 
     return (
-      <div className="absolute right-[190px] bottom-[120px] z-99 flex flex-col items-end gap-2 text-[#4e402e]">
+      <div className="absolute right-[190px] bottom-[120px] z-100 flex flex-col items-end gap-2 text-[#4e402e]">
+        <style>{`.signature-name-input::placeholder { color: #999999; font-size: 26px; }`}</style>
         <input
           name="signature-name"
-          className={`h-[36px] bg-transparent border-b-2 border-dashed text-center outline-none w-[120px] ${signatureError ? 'border-red-500' : 'border-[#4e402e]'}`}
+          className={`signature-name-input h-[36px] bg-transparent border-b-2 border-dashed text-center outline-none w-[240px] ${signatureError ? 'border-red-500' : 'border-[#4e402e]'}`}
           style={{ fontSize: '26px' }}
           autoComplete="off"
+          placeholder="请郑重签下你的姓名"
           value={signatureName}
           maxLength={12}
           onChange={(e) => handleSignatureNameChange(e.target.value)}