Feat: Add TextCursor modifier for cursor styling in TextField/SecureField

- Add cursorColor to Palette protocol with HSL-computed values for all SystemPalette presets
- Create TextCursorStyle with shapes (block, bar, underscore) and animations (none, blink, pulse)
- Add .textCursor(_:) View modifier propagating through environment
- Update TextField and SecureField to use cursorColor and respect cursor style
- Add 17 tests for TextCursorStyle

Sources/TUIkitExample/Pages/TextFieldPage.swift

@@ -1,4 +1,4 @@
-//  🖥️ TUIKit — Terminal UI Kit for Swift
+//  TUIKit - Terminal UI Kit for Swift
 //  TextFieldPage.swift
 //
 //  Created by LAYERED.work
@@ -10,42 +10,76 @@ import TUIkit
 ///
 /// Shows interactive text field features including:
 /// - Basic text input with cursor
+/// - Cursor styles (block, bar, underscore)
+/// - Cursor animations (none, blink, pulse)
+/// - Cursor speeds (slow, regular, fast)
 /// - Cursor navigation (left/right/home/end)
 /// - Text editing (insert, backspace, delete)
 /// - onSubmit action
 /// - Disabled state
-/// - Live state display
 struct TextFieldPage: View {
-    @State var username: String = ""
-    @State var email: String = ""
+    @State var demoText: String = ""
     @State var searchQuery: String = ""
     @State var disabledText: String = "Cannot edit"
     @State var submittedValue: String = ""
 
+    @State var cursorShapeIndex: Int = 0
+    @State var cursorAnimationIndex: Int = 0
+    @State var cursorSpeedIndex: Int = 1  // Start at regular
+
+    private let shapes: [TextCursorStyle.Shape] = [.block, .bar, .underscore]
+    private let animations: [TextCursorStyle.Animation] = [.none, .blink, .pulse]
+    private let speeds: [TextCursorStyle.Speed] = [.slow, .regular, .fast]
+
+    private var currentShape: TextCursorStyle.Shape {
+        shapes[cursorShapeIndex]
+    }
+
+    private var currentAnimation: TextCursorStyle.Animation {
+        animations[cursorAnimationIndex]
+    }
+
+    private var currentSpeed: TextCursorStyle.Speed {
+        speeds[cursorSpeedIndex]
+    }
+
+    private var shapeLabel: String {
+        switch currentShape {
+        case .block: "█ Block"
+        case .bar: "│ Bar"
+        case .underscore: "▁ Underscore"
+        }
+    }
+
+    private var animationLabel: String {
+        switch currentAnimation {
+        case .none: "Static"
+        case .blink: "Blink"
+        case .pulse: "Pulse"
+        }
+    }
+
+    private var speedLabel: String {
+        switch currentSpeed {
+        case .slow: "Slow"
+        case .regular: "Regular"
+        case .fast: "Fast"
+        }
+    }
+
     var body: some View {
         VStack(alignment: .leading, spacing: 1) {
 
-            DemoSection("Basic Text Fields") {
+            DemoSection("Cursor Demo") {
                 VStack(alignment: .leading, spacing: 1) {
                     HStack(spacing: 1) {
-                        Text("Username:").foregroundStyle(.palette.foregroundSecondary)
-                        TextField("Username", text: $username)
+                        Text("Input:").foregroundStyle(.palette.foregroundSecondary)
+                        TextField("Type here...", text: $demoText)
                     }
-                    HStack(spacing: 1) {
-                        Text("Email:").foregroundStyle(.palette.foregroundSecondary)
-                        TextField("Email", text: $email, prompt: Text("you@example.com"))
-                    }
-                }
-            }
-
-            DemoSection("With onSubmit") {
-                VStack(alignment: .leading, spacing: 1) {
                     HStack(spacing: 1) {
                         Text("Search:").foregroundStyle(.palette.foregroundSecondary)
                         TextField("Search", text: $searchQuery)
-                            .onSubmit {
-                                submittedValue = searchQuery
-                            }
+                            .onSubmit { submittedValue = searchQuery }
                     }
                     if !submittedValue.isEmpty {
                         HStack(spacing: 1) {
@@ -53,6 +87,7 @@ struct TextFieldPage: View {
                             Text(submittedValue).foregroundStyle(.palette.success)
                         }
                     }
+                    Text("Cursor style set on container, inherited by all fields").dim()
                 }
             }
 
@@ -65,37 +100,31 @@ struct TextFieldPage: View {
                 }
             }
 
-            DemoSection("Current Values") {
-                VStack(alignment: .leading, spacing: 1) {
-                    HStack(spacing: 1) {
-                        Text("Username:").foregroundStyle(.palette.foregroundSecondary)
-                        Text(username.isEmpty ? "(empty)" : "\"\(username)\"").foregroundStyle(.palette.accent)
-                    }
-                    HStack(spacing: 1) {
-                        Text("Email:").foregroundStyle(.palette.foregroundSecondary)
-                        Text(email.isEmpty ? "(empty)" : "\"\(email)\"").foregroundStyle(.palette.accent)
-                    }
-                    HStack(spacing: 1) {
-                        Text("Search:").foregroundStyle(.palette.foregroundSecondary)
-                        Text(searchQuery.isEmpty ? "(empty)" : "\"\(searchQuery)\"").foregroundStyle(.palette.accent)
+            HStack(alignment: .top, spacing: 3) {
+                DemoSection("Keyboard Controls") {
+                    VStack(alignment: .leading) {
+                        Text("[←] [→] Move cursor left/right").dim()
+                        Text("[Home] [End] Jump to start/end").dim()
+                        Text("[Backspace] Delete before cursor").dim()
+                        Text("[Delete] Delete at cursor").dim()
+                        Text("[Enter] Submit (triggers onSubmit)").dim()
+                        Text("[Tab] Move to next field").dim()
                     }
                 }
-            }
 
-            DemoSection("Keyboard Controls") {
-                VStack(alignment: .leading) {
-                    Text("Type any character to insert at cursor").dim()
-                    Text("[←] [→] Move cursor left/right").dim()
-                    Text("[Home] [End] Jump to start/end").dim()
-                    Text("[Backspace] Delete before cursor").dim()
-                    Text("[Delete] Delete at cursor").dim()
-                    Text("[Enter] Submit (triggers onSubmit)").dim()
-                    Text("[Tab] Move to next field").dim()
+                DemoSection("Cursor Settings") {
+                    VStack(alignment: .leading) {
+                        Text("[F1] Shape: Block, Bar, Underscore").dim()
+                        Text("[F2] Animation: Static, Blink, Pulse").dim()
+                        Text("[F3] Speed: Slow, Regular, Fast").dim()
+                    }
                 }
             }
 
             Spacer()
         }
+        .textCursor(currentShape, animation: currentAnimation, speed: currentSpeed)
+        .statusBarItems(cursorStatusBarItems)
         .appHeader {
             HStack {
                 Text("TextField Demo").bold().foregroundStyle(.palette.accent)
@@ -104,4 +133,18 @@ struct TextFieldPage: View {
             }
         }
     }
+
+    private var cursorStatusBarItems: [any StatusBarItemProtocol] {
+        [
+            StatusBarItem(shortcut: Shortcut.f1, label: shapeLabel) {
+                cursorShapeIndex = (cursorShapeIndex + 1) % shapes.count
+            },
+            StatusBarItem(shortcut: Shortcut.f2, label: animationLabel) {
+                cursorAnimationIndex = (cursorAnimationIndex + 1) % animations.count
+            },
+            StatusBarItem(shortcut: Shortcut.f3, label: speedLabel) {
+                cursorSpeedIndex = (cursorSpeedIndex + 1) % speeds.count
+            },
+        ]
+    }
 }