docs: 更新需求文档至v0.5并归档开发进度；修复大文件上传与二维码海报

- 需求文档升级到 v0.5：补充二维码海报保存文件名默认格式、大文件上传三层限制（IIS+ASP.NET+前端）部署约束、新增第11章开发进度状态归档（已上线功能/已修复缺陷/已知限制/后续优化）
- 后端 FileController.Upload 增加 [RequestFormLimits(MultipartBodyLengthLimit=220_200_960)]，修复>128MB multipart 上传被拒
- 前端 UploadView 二维码海报：修正 drawImage 缩放错位、顶部logo/标题垂直居中、分区标题间距、大小与有效期分行显示；保存文件名改为 文传易取件码-取件码(原文件名)-流水号.png
- 新增部署脚本：apply_backend.ps1 / force_dll.ps1（app_offline 解锁DLL）/ ftp_fe.ps1 / ftp_diag.ps1 / ftp_apply.ps1 / _diag/check_dll.ps1

(部署手册 IIS部署与FTP发布.md 仅含编码/BOM 差异，未纳入本次提交)

deploy/ftp_diag.ps1

@@ -0,0 +1,29 @@
+# Download web.config + list logs dir for upload-failure diagnosis
+$ErrorActionPreference = "Continue"
+$FtpHost="116.198.221.125"; $FtpPort=21; $FtpUser="wenchuanyi"; $FtpPass="r7P^f*v7rFts"
+$Out = "D:\CodeBuddy\Pros\WenChuanyi\deploy\_diag"
+New-Item -ItemType Directory -Force -Path $Out | Out-Null
+function NewR($p,$m,$to=60000){ $u="ftp://${FtpHost}:${FtpPort}/"+$p.TrimStart('/'); $r=[System.Net.FtpWebRequest]::Create($u); $r.Method=$m; $r.Credentials=New-Object System.Net.NetworkCredential($FtpUser,$FtpPass); $r.UsePassive=$true; $r.UseBinary=$true; $r.KeepAlive=$false; $r.Timeout=$to; $r }
+function Down($rp,$lp){
+  try{
+    $r=NewR $rp ([System.Net.WebRequestMethods+Ftp]::DownloadFile)
+    $resp=$r.GetResponse(); $fs=[IO.File]::Create($lp)
+    $s=$resp.GetResponseStream(); $b=New-Object byte[] 65536
+    while(($n=$s.Read($b,0,65536)) -gt 0){ $fs.Write($b,0,$n) }
+    $fs.Close(); $s.Close(); $resp.Close()
+    Write-Host "DOWN OK $rp -> $lp"
+  }catch{ Write-Host "DOWN FAIL $rp : $($_.Exception.Message)" }
+}
+function ListF($p){
+  try{
+    $r=NewR $p ([System.Net.WebRequestMethods+Ftp]::ListDirectoryDetails)
+    $resp=$r.GetResponse(); $sr=New-Object IO.StreamReader($resp.GetResponseStream(),[Text.Encoding]::UTF8)
+    $txt=$sr.ReadToEnd(); $sr.Close(); $resp.Close()
+    return $txt
+  }catch{ return "ERR $($_.Exception.Message)" }
+}
+Down "/wwwroot/web.config" "$Out\server-web.config"
+Write-Host "=== logs dir ==="
+(ListF "/wwwroot/logs/") | ForEach-Object { Write-Host $_ }
+Write-Host "=== wwwroot dir ==="
+(ListF "/wwwroot/") | ForEach-Object { Write-Host $_ }