Shrink lock screen password dots to fit the field

Long passwords used to overflow the input field and clip with no
feedback that typing was still registering. Scale the dot size and
letter spacing down as the password grows, like macOS, so every
keystroke stays visible.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

shell/plugins/lock/LockView.qml

@@ -24,6 +24,11 @@ Item {
   readonly property int fieldFontSize: Math.round(Style.font.heading * 1.125)
   readonly property int passwordDotFontSize: Math.round(Style.font.heading * 1.33)
   readonly property int passwordDotLetterSpacing: Math.round(Style.font.heading * 0.19)
+  // Shrink the dots to fit once the password outgrows the field, so every
+  // keystroke stays visible — otherwise long passwords clip with no feedback.
+  readonly property real passwordDotScale: dotMetrics.advanceWidth > 0
+    ? Math.min(1, (passwordInput.width - 4) / dotMetrics.advanceWidth)
+    : 1
   readonly property bool showPasswordCursor: inputEnabled && !authenticatingPassword && failureMessage.length === 0
   readonly property bool errorState: failureMessage.length > 0
   readonly property var inputBorderSpec: errorState
@@ -68,6 +73,16 @@ Item {
     if (inputEnabled) Qt.callLater(forcePasswordFocus)
   }
 
+  // Measures the masked password at full size; passwordDotScale compares this
+  // against the field width to decide how far the dots must shrink to fit.
+  TextMetrics {
+    id: dotMetrics
+    font.family: Style.font.family
+    font.pixelSize: root.passwordDotFontSize
+    font.letterSpacing: root.passwordDotLetterSpacing
+    text: "●".repeat(passwordInput.text.length)
+  }
+
   Rectangle {
     anchors.fill: parent
     color: Color.background
@@ -131,8 +146,8 @@ Item {
         selectionColor: Color.lock.selection
         selectedTextColor: Color.lock.text
         font.family: Style.font.family
-        font.pixelSize: text.length > 0 ? root.passwordDotFontSize : root.fieldFontSize
-        font.letterSpacing: text.length > 0 ? root.passwordDotLetterSpacing : 0
+        font.pixelSize: text.length > 0 ? Math.max(1, Math.floor(root.passwordDotFontSize * root.passwordDotScale)) : root.fieldFontSize
+        font.letterSpacing: text.length > 0 ? root.passwordDotLetterSpacing * root.passwordDotScale : 0
         cursorVisible: activeFocus && root.showPasswordCursor && text.length > 0
         cursorDelegate: Rectangle {
           width: 2