fix(ci): 健壮化 Inno Setup 安装 + 部署仅保留最新安装包

- 新增 install-innosetup.ps1：校验下载大小、检查安装程序退出码、双
  Program Files 目录定位 ISCC，修复原内联命令静默成功但没真正装上的问题
  （SYSTEM 账户下 Invoke-WebRequest 无 -UseBasicParsing + 未检查退出码）
- provision/compile-windows.sh 在两个 Program Files 目录查找 ISCC
- deploy.sh 发布安装包到 /opt/jiu/downloads 前先清旧包，仅保留最新版本

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/ci/provision-windows.sh

@@ -18,17 +18,16 @@ CUR="${STAMP_DIR}/.flutter-version-win.cur"
 mkdir -p "$STAMP_DIR"
 
 # --- ensure Inno Setup (ISCC) for building the installer (always checked) ---
-ISCC="/c/Program Files (x86)/Inno Setup 6/ISCC.exe"
-if [ ! -f "$ISCC" ]; then
+# ISCC installs to Program Files (x86) (32-bit app); check both to be safe.
+ISCC_X86="/c/Program Files (x86)/Inno Setup 6/ISCC.exe"
+ISCC_X64="/c/Program Files/Inno Setup 6/ISCC.exe"
+if [ ! -f "$ISCC_X86" ] && [ ! -f "$ISCC_X64" ]; then
   echo "==> installing Inno Setup 6 (silent)"
-  # Canonical "latest stable" entry point (redirects to the GitHub release asset).
-  INNO_URL="https://jrsoftware.org/download.php/is.exe"
-  powershell -NoProfile -Command \
-    "Invoke-WebRequest -Uri '${INNO_URL}' -OutFile \"\$env:TEMP\\innosetup.exe\""
-  powershell -NoProfile -Command \
-    "Start-Process -Wait -FilePath \"\$env:TEMP\\innosetup.exe\" -ArgumentList '/VERYSILENT','/SUPPRESSMSGBOXES','/NORESTART','/SP-'"
-  if [ ! -f "$ISCC" ]; then
-    echo "ERROR: Inno Setup install failed — ISCC not found at '$ISCC'." >&2
+  # Robust installer (checks download size + installer exit code) — inline
+  # bash->powershell quoting was the original failure; a .ps1 avoids it.
+  powershell -NoProfile -ExecutionPolicy Bypass -File "${SCRIPT_DIR}/install-innosetup.ps1"
+  if [ ! -f "$ISCC_X86" ] && [ ! -f "$ISCC_X64" ]; then
+    echo "ERROR: Inno Setup install failed — ISCC not found." >&2
     exit 1
   fi
   echo "==> Inno Setup installed."