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/force_dll.ps1

@@ -0,0 +1,24 @@
+# Force-overwrite WenChuanyi.Api.dll via app_offline (dll size identical -> size-check skipped it)
+$ErrorActionPreference = "Continue"
+$h="116.198.221.125"; $p=21; $u="wenchuanyi"; $pw="r7P^f*v7rFts"
+$LocalDll="D:\CodeBuddy\Pros\WenChuanyi\backend\WenChuanyi.Api\bin\Release\net8.0\publish\WenChuanyi.Api.dll"
+$Log="D:\CodeBuddy\Pros\WenChuanyi\deploy\force_dll.log"
+Set-Content $Log "=== force dll start $(Get-Date -Format 'HH:mm:ss') ===" -Encoding UTF8
+function L([string]$m){ Add-Content $Log $m -Encoding UTF8; Write-Host $m }
+function NewR([string]$path,[string]$m,[int]$t=90000){ $r=[System.Net.FtpWebRequest]::Create("ftp://${h}:${p}/"+$path.TrimStart('/')); $r.Method=$m; $r.Credentials=New-Object System.Net.NetworkCredential($u,$pw); $r.UsePassive=$true; $r.UseBinary=$true; $r.KeepAlive=$false; $r.Timeout=$t; return $r }
+function UpRaw([string]$lp,[string]$rp){
+  $b=[IO.File]::ReadAllBytes($lp); $r=NewR $rp ([System.Net.WebRequestMethods+Ftp]::UploadFile) 300000
+  $r.ContentLength=$b.Length; $s=$r.GetRequestStream(); try{ $s.Write($b,0,$b.Length) } finally { $s.Close() }
+  $resp=$r.GetResponse(); try{ $resp.Close() }catch{}; L "UP $rp len=$($b.Length)"
+}
+# 1. stop app
+Set-Content "$env:TEMP\app_offline.htm" "maintenance" -Encoding UTF8
+try{ UpRaw "$env:TEMP\app_offline.htm" "/wwwroot/app_offline.htm" }catch{ L "offline up err: $($_.Exception.Message)" }
+L "wait 7s..."; Start-Sleep -Seconds 7
+# 2. force dll
+try{ UpRaw $LocalDll "/wwwroot/WenChuanyi.Api.dll"; L "DLL FORCE-UP OK" }catch{ L "DLL FAIL: $($_.Exception.Message)" }
+Start-Sleep -Seconds 1
+# 3. remove app_offline -> restart
+try{ $r=NewR "/wwwroot/app_offline.htm" ([System.Net.WebRequestMethods+Ftp]::DeleteFile); $resp=$r.GetResponse(); try{$resp.Close()}catch{}; L "app_offline removed (restarting)" }catch{ L "offline del err: $($_.Exception.Message)" }
+Remove-Item "$env:TEMP\app_offline.htm" -ErrorAction SilentlyContinue
+L "=== force dll end ==="