feat(autofill): "Clear the field before typing" setting (default ON)

The Ctrl+A + Del sent before each field misbehaves on targets where Ctrl+A
isn't select-all (terminals, some remote desktops). New synced setting
(autofillClearField, Settings > Autofill) gates it: JS appends clear=0 to
cmd://autofill/execute when off; ExecuteAutofill wraps the three
SendSelectAllAndDelete calls behind AClearFirst. Absent param = ON, so
existing behavior is unchanged.

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

delphi-backend/Source/PM.Bridge.pas

@@ -171,9 +171,10 @@ type
     // the caller trays it after the fill.
     // Returns False when nothing was typed: elevated target (UIPI would
     // silently drop the keystrokes) or focus never left our own window.
+    // AClearFirst: send Ctrl+A + Del before each field (user setting).
     function ExecuteAutofill(ATargetHWND: HWND;
       const AUsername, APassword: string; AUsernameOnly: Boolean = False;
-      ARestoreAfter: Boolean = False): Boolean;
+      ARestoreAfter: Boolean = False; AClearFirst: Boolean = True): Boolean;
     property SecureClipboard: TSecureClipboard read FSecureClipboard;
     property TrayAdded: Boolean read FTrayAdded;
     property AutofillRegistered: Boolean read FAutofillRegistered;
@@ -1187,10 +1188,21 @@ end;
 
 function TPMBridge.ExecuteAutofill(ATargetHWND: HWND;
   const AUsername, APassword: string; AUsernameOnly: Boolean = False;
-  ARestoreAfter: Boolean = False): Boolean;
+  ARestoreAfter: Boolean = False; AClearFirst: Boolean = True): Boolean;
 const
   MinimizeSettleMs   = 80;
   FocusSettleDelayMs = 120;
+
+  // Ctrl+A + Del to empty the target field — skipped when the user turned
+  // "Clear the field before typing" off (Ctrl+A isn't select-all everywhere:
+  // terminals, some remote desktops).
+  procedure ClearFieldIfWanted;
+  begin
+    if not AClearFirst then Exit;
+    SendSelectAllAndDelete;
+    Sleep(60);
+  end;
+
 var
   OwnFormHwnd: HWND;
 begin
@@ -1233,28 +1245,24 @@ begin
   // no password. Used by the quick-search right-click / Shift+Enter path.
   if AUsernameOnly then
   begin
-    SendSelectAllAndDelete;
-    Sleep(60);
+    ClearFieldIfWanted;
     SendUnicodeString(AUsername);
     Exit;
   end;
 
   if AUsername = '' then
   begin
-    SendSelectAllAndDelete;
-    Sleep(60);
+    ClearFieldIfWanted;
     SendUnicodeString(APassword);
     Exit;
   end;
 
-  SendSelectAllAndDelete;
-  Sleep(60);
+  ClearFieldIfWanted;
   SendUnicodeString(AUsername);
   Sleep(200);
   SendVKey(VK_TAB);
   Sleep(200);
-  SendSelectAllAndDelete;
-  Sleep(60);
+  ClearFieldIfWanted;
   SendUnicodeString(APassword);
 end;