Adds /FORCEUPGRADE command line parameter

Allows skipping the upgrade confirmation prompt by providing the `/FORCEUPGRADE` command line parameter.
This enables unattended upgrades for automation scenarios.

installer/installer.iss

@@ -80,6 +80,20 @@ var
   PreviousVersion: String;
   IsUpgrade: Boolean;
 
+// Check if a command line parameter exists
+function CmdLineParamExists(const Param: string): Boolean;
+var
+  I: Integer;
+begin
+  Result := False;
+  for I := 1 to ParamCount do
+    if CompareText(ParamStr(I), Param) = 0 then
+    begin
+      Result := True;
+      Exit;
+    end;
+end;
+
 // Check if a previous version is installed
 function GetPreviousVersion(): String;
 var
@@ -114,6 +128,9 @@ begin
   IsUpgrade := (PreviousVersion <> '');
   
   if IsUpgrade then
+  begin
+    // Check for /FORCEUPGRADE parameter to skip confirmation
+    if not CmdLineParamExists('/FORCEUPGRADE') then
     begin
       // Show upgrade message
       Message := FmtMessage(CustomMessage('UpgradeDetected'), [PreviousVersion]) + #13#10#13#10 +
@@ -124,6 +141,7 @@ begin
         Result := False;
       end;
     end;
+  end;
 end;
 
 // Show appropriate welcome message