Fix: passkey sound now layers in on password fields

RemSound's password boxes are deliberately NOT PasswordChar-masked (a screen-reader user can't see
a mask), so the key-click hook's "is this a password field?" check (UseSystemPasswordChar /
PasswordChar) was always false and the distinct passkey.wav never played. Password fields now mark
themselves with Tag = KeyClickService.PasswordFieldTag, and the hook checks that (keeping the
masking-flag check as a fallback). Tagged both password fields - ProfilePasswordDialog (which all
password entry routes through, including the send/receive streaming gate) and
ProfilePasswordManagerDialog. So a key click + passkey now layer together on every password keystroke.

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

src/RemSound.App/KeyClickService.cs

@@ -20,6 +20,12 @@ internal static class KeyClickService
 {
     private const int WM_CHAR = 0x0102;
 
+    /// <summary>Tag value a password entry field sets on itself (<c>control.Tag = PasswordFieldTag</c>)
+    /// so the key-click hook layers in the distinct passkey sound. RemSound's password boxes are
+    /// deliberately NOT PasswordChar-masked (a screen-reader user can't see the mask anyway), so
+    /// there's no built-in flag to detect - they mark themselves with this tag instead.</summary>
+    public const string PasswordFieldTag = "remsound-password-field";
+
     private static KeyClickPlayer? player;
     private static MessageFilter? filter;
 
@@ -58,7 +64,10 @@ internal static class KeyClickService
         if (!Enabled || player is null) return;
         // The WM_CHAR target window is the focused control. Click only when it's an edit field.
         if (System.Windows.Forms.Control.FromHandle(hwnd) is not System.Windows.Forms.TextBoxBase edit) return;
-        var isPassword = edit is System.Windows.Forms.TextBox tb && (tb.UseSystemPasswordChar || tb.PasswordChar != '\0');
+        // A password field is marked by its Tag (RemSound's boxes aren't PasswordChar-masked), with
+        // a fallback to the standard masking flags for any conventionally-masked box.
+        var isPassword = (edit.Tag as string) == PasswordFieldTag
+            || (edit is System.Windows.Forms.TextBox tb && (tb.UseSystemPasswordChar || tb.PasswordChar != '\0'));
         player.PlayClick(isPassword);
     }
 

src/RemSound.App/ProfilePasswordDialog.cs

@@ -38,6 +38,8 @@ internal static class ProfilePasswordDialog
             Dock = DockStyle.Top,
             Width = 400,
             AccessibleName = $"Password for profile {profileTitle}",
+            // Mark as a password field so the key-click hook layers in the passkey sound.
+            Tag = KeyClickService.PasswordFieldTag,
         };
         var hint = new Label
         {

src/RemSound.App/ProfilePasswordManagerDialog.cs

@@ -60,7 +60,7 @@ internal static class ProfilePasswordManagerDialog
             catch { current = ""; }
 
             var label = new Label { Text = title, AutoSize = true, Anchor = AnchorStyles.Left, Padding = new Padding(0, 6, 10, 6) };
-            var box = new TextBox { Text = current, Anchor = AnchorStyles.Left | AnchorStyles.Right, AccessibleName = $"Password for profile {title}" };
+            var box = new TextBox { Text = current, Anchor = AnchorStyles.Left | AnchorStyles.Right, AccessibleName = $"Password for profile {title}", Tag = KeyClickService.PasswordFieldTag };
             grid.Controls.Add(label);
             grid.Controls.Add(box);
             rows.Add((title, current, box));