fix(windows): switch to system-wide VC++ redistributable, purge legacy app-local CRT DLLs, and harden documentation viewer

frontend/INSTALL.md

@@ -49,7 +49,7 @@ flutter build apk --release --obfuscate --split-debug-info=build/app/outputs/sym
 The Windows client runs natively on Windows 10 and Windows 11 (64-bit).
 
 ### Prerequisites:
-- **Microsoft Visual C++ 2015–2022 Redistributable (x64)** (Core runtime libraries `vcruntime140_1.dll`, `msvcp140.dll`, etc. are bundled directly with the release binaries; the installer also automatically installs the full redistributable if missing).
+- **Microsoft Visual C++ 2015–2022 Redistributable (x64)** (v14.30+ / VS 2022 toolset; the installer automatically checks system compatibility and installs the official Microsoft redistributable silently if missing or outdated).
 - **Microsoft .NET Desktop Runtime 6.0/8.0+ (x64)** (automatically detected and installed silently by setup if missing).
 
 ---
@@ -73,12 +73,11 @@ flutter build windows --release --obfuscate --split-debug-info=build/windows/sym
 
 ### B. Compiling the Windows Inno Setup Installer (`TIS_RMS_Client.iss`)
 
-The installer script [`frontend/TIS_RMS_Client.iss`](file:///d:/Capstone/TIS_RIS_Server_Manager/TIS_RMS/frontend/TIS_RMS_Client.iss) packages the app into an ultra-compact standalone setup file (`TIS_RMS_Client_Setup_v<version>.exe` ~**16.7 MB**).
+The installer script [`frontend/TIS_RMS_Client.iss`](file:///f:/SumbrerongBato/tis_rms_server/frontend/TIS_RMS_Client.iss) packages the app into an ultra-compact standalone setup file (`TIS_RMS_Client_Setup_v<version>.exe` ~**16.7 MB**).
 
 #### Features:
 - **Small File Size (~17 MB)**: Uses `lzma2/ultra64` solid 64MB dictionary compression.
-- **Bundled VC++ Runtime DLLs**: Packages MSVC CRT libraries (`vcruntime140.dll`, `vcruntime140_1.dll`, `msvcp140.dll`, etc.) directly into the application folder to prevent missing DLL crashes.
-- **Automated VC++ & .NET Runtime Setup**: Checks system registry and automatically installs Microsoft Visual C++ 2015-2022 Redistributable and Microsoft .NET Desktop Runtime silently if missing.
+- **Automated System-Wide VC++ & .NET Runtime Setup**: Automatically detects whether a compatible Visual Studio 2022 (v14.30+) x64 runtime is installed in Windows (`System32`) and silently installs Microsoft's official `vc_redist.x64.exe` if missing or outdated. Also purges legacy app-local CRT DLLs to prevent ABI mismatch crashes.
 - **Selectable Destination Path**: Lets the user choose where to install (defaults to `C:\Program Files\TIS RMS Client`).
 - **Desktop Shortcut Checkbox**: Optional checkbox on the tasks page to create a desktop shortcut with the official school icon logo.
 - **Start Menu & Uninstaller**: Registers a Start Menu program group and includes a clean uninstaller in Windows *Apps & Features* / *Settings*.

frontend/TIS_RMS_Client.iss

@@ -58,12 +58,19 @@ Name: "english"; MessagesFile: "compiler:Default.isl"
 Name: "desktopicon"; Description: "{cm:CreateDesktopIcon}"; GroupDescription: "{cm:AdditionalIcons}"; Flags: unchecked
 
 [Files]
-; Main application binaries and libraries (excludes unnecessary dev .lib and .exp files for smaller footprint)
+; Main application binaries and libraries (excludes unnecessary dev .lib/.exp and prevents app-local CRT poisoning)
 Source: "build\windows\x64\runner\Release\*.exe"; DestDir: "{app}"; Flags: ignoreversion
-Source: "build\windows\x64\runner\Release\*.dll"; DestDir: "{app}"; Flags: ignoreversion
+Source: "build\windows\x64\runner\Release\*.dll"; DestDir: "{app}"; Flags: ignoreversion; Excludes: "msvcp140*.dll,vcruntime140*.dll,concrt140.dll,vccorlib140.dll"
 Source: "build\windows\x64\runner\Release\data\*"; DestDir: "{app}\data"; Flags: ignoreversion recursesubdirs createallsubdirs
 Source: "{#MyAppIcon}"; DestDir: "{app}"; DestName: "app_icon.ico"; Flags: ignoreversion
 
+[InstallDelete]
+; Clean up any legacy app-local MSVC CRT DLLs from older installations so app always uses C:\Windows\System32
+Type: files; Name: "{app}\msvcp140*.dll"
+Type: files; Name: "{app}\vcruntime140*.dll"
+Type: files; Name: "{app}\concrt140.dll"
+Type: files; Name: "{app}\vccorlib140.dll"
+
 [Icons]
 ; Start menu shortcut
 Name: "{group}\{#MyAppName}"; Filename: "{app}\{#MyAppExeName}"; IconFilename: "{app}\app_icon.ico"
@@ -77,14 +84,30 @@ Name: "{autodesktop}\{#MyAppName}"; Filename: "{app}\{#MyAppExeName}"; IconFilen
 Filename: "{app}\{#MyAppExeName}"; Description: "{cm:LaunchProgram,{#StringChange(MyAppName, '&', '&&')}}"; Flags: nowait postinstall skipifsilent
 
 [Code]
-// Helper function to verify Microsoft Visual C++ 2015-2022 Redistributable (x64)
-function IsVCRedistInstalled: Boolean;
+// Helper function to verify Microsoft Visual C++ 2015-2022 Redistributable (x64, Minor >= 30 for VS 2022 compatibility)
+function IsVCRedistCompatible: Boolean;
 var
   installed: Cardinal;
+  minor: Cardinal;
 begin
-  Result := RegQueryDWordValue(HKLM64, 'SOFTWARE\Microsoft\VisualStudio\14.0\VC\Runtimes\X64', 'Installed', installed) and (installed = 1);
+  Result := False;
+  if RegQueryDWordValue(HKLM64, 'SOFTWARE\Microsoft\VisualStudio\14.0\VC\Runtimes\X64', 'Installed', installed) and (installed = 1) then
+  begin
+    if RegQueryDWordValue(HKLM64, 'SOFTWARE\Microsoft\VisualStudio\14.0\VC\Runtimes\X64', 'Minor', minor) then
+      Result := (minor >= 30) // Minor 30+ indicates Visual Studio 2022 or newer
+    else
+      Result := True;
+  end;
   if not Result then
-    Result := RegQueryDWordValue(HKLM, 'SOFTWARE\Microsoft\VisualStudio\14.0\VC\Runtimes\X64', 'Installed', installed) and (installed = 1);
+  begin
+    if RegQueryDWordValue(HKLM, 'SOFTWARE\Microsoft\VisualStudio\14.0\VC\Runtimes\X64', 'Installed', installed) and (installed = 1) then
+    begin
+      if RegQueryDWordValue(HKLM, 'SOFTWARE\Microsoft\VisualStudio\14.0\VC\Runtimes\X64', 'Minor', minor) then
+        Result := (minor >= 30)
+      else
+        Result := True;
+    end;
+  end;
 end;
 
 // Helper function to verify Microsoft .NET Desktop Runtime
@@ -101,8 +124,8 @@ var
 begin
   if CurStep = ssPostInstall then
   begin
-    // If Microsoft Visual C++ 2015-2022 Redistributable (x64) is not installed, automatically install it silently
-    if not IsVCRedistInstalled then
+    // If Microsoft Visual C++ 2015-2022 Redistributable (x64) is not installed or outdated (< VS 2022), automatically install it silently
+    if not IsVCRedistCompatible then
     begin
       Exec('powershell.exe', '-NoProfile -ExecutionPolicy Bypass -Command "$ProgressPreference = ''SilentlyContinue''; try { if (Get-Command winget -ErrorAction SilentlyContinue) { winget install --id Microsoft.VCRedist.2015+.x64 --silent --accept-package-agreements --accept-source-agreements } else { $url = ''https://aka.ms/vs/17/release/vc_redist.x64.exe''; $out = ''$env:TEMP\vc_redist.x64.exe''; Invoke-WebRequest -Uri $url -OutFile $out; Start-Process -FilePath $out -ArgumentList ''/install /quiet /norestart'' -Wait } } catch {}"', '', SW_HIDE, ewWaitUntilTerminated, ResultCode);
     end;

frontend/lib/ui/screens/documentation/documentation_screen.dart

@@ -339,7 +339,9 @@ class _WindowsDocViewState extends State<_WindowsDocView> {
 
     if (_isInitialized) {
       try {
-        _controller.dispose();
+        _controller.dispose().catchError((e) {
+          debugPrint('[DocumentationScreen] webview async dispose error: $e');
+        });
       } catch (e) {
         debugPrint('[DocumentationScreen] webview dispose error: $e');
       }