Add contextual help dialog (Ctrl+?)

- Created new help dialog that displays all currently active key bindings
- Help is contextual: shows different bindings based on focused panel
- Bindings are automatically categorized into General, Control Key Shortcuts, and Other
- Added Ctrl+? keybinding to open the help dialog
- Dialog is scrollable for when there are many bindings
- Inherits from readOnlyScrollDialog for consistent behavior

Assisted-By: docker-agent

Author: masegraye

pkg/tui/dialog/help.go

@@ -0,0 +1,158 @@
+package dialog
+
+import (
+	"fmt"
+	"strings"
+
+	"charm.land/bubbles/v2/key"
+	tea "charm.land/bubbletea/v2"
+	"charm.land/lipgloss/v2"
+
+	"github.com/docker/docker-agent/pkg/tui/core/layout"
+	"github.com/docker/docker-agent/pkg/tui/styles"
+)
+
+// helpDialog displays all currently active key bindings in a scrollable dialog.
+type helpDialog struct {
+	readOnlyScrollDialog
+	bindings []key.Binding
+}
+
+// NewHelpDialog creates a new help dialog that displays all active key bindings.
+func NewHelpDialog(bindings []key.Binding) Dialog {
+	d := &helpDialog{
+		bindings: bindings,
+	}
+	d.readOnlyScrollDialog = newReadOnlyScrollDialog(
+		readOnlyScrollDialogSize{
+			widthPercent:  70,
+			minWidth:      60,
+			maxWidth:      100,
+			heightPercent: 80,
+			heightMax:     40,
+		},
+		d.renderContent,
+	)
+	d.helpKeys = []string{"↑↓", "scroll", "Esc", "close"}
+	return d
+}
+
+// renderContent renders the help dialog content.
+func (d *helpDialog) renderContent(contentWidth, maxHeight int) []string {
+	titleStyle := styles.DialogTitleStyle
+	separatorStyle := styles.DialogSeparatorStyle
+	keyStyle := styles.DialogHelpStyle.Foreground(styles.TextSecondary).Bold(true)
+	descStyle := styles.DialogHelpStyle
+
+	lines := []string{
+		titleStyle.Render("Active Key Bindings"),
+		separatorStyle.Render(strings.Repeat("─", contentWidth)),
+		"",
+	}
+
+	// Group bindings by category for better organization
+	// We'll do a simple categorization based on key prefixes
+	globalBindings := []key.Binding{}
+	ctrlBindings := []key.Binding{}
+	otherBindings := []key.Binding{}
+
+	for _, binding := range d.bindings {
+		if len(binding.Keys()) == 0 {
+			continue
+		}
+		keyStr := binding.Keys()[0]
+		if strings.HasPrefix(keyStr, "ctrl+") {
+			ctrlBindings = append(ctrlBindings, binding)
+		} else if keyStr == "esc" || keyStr == "enter" || keyStr == "tab" {
+			globalBindings = append(globalBindings, binding)
+		} else {
+			otherBindings = append(otherBindings, binding)
+		}
+	}
+
+	// Render global bindings
+	if len(globalBindings) > 0 {
+		lines = append(lines, styles.DialogHelpStyle.Bold(true).Render("General"))
+		lines = append(lines, "")
+		for _, binding := range globalBindings {
+			lines = append(lines, d.formatBinding(binding, keyStyle, descStyle, contentWidth))
+		}
+		lines = append(lines, "")
+	}
+
+	// Render ctrl bindings
+	if len(ctrlBindings) > 0 {
+		lines = append(lines, styles.DialogHelpStyle.Bold(true).Render("Control Key Shortcuts"))
+		lines = append(lines, "")
+		for _, binding := range ctrlBindings {
+			lines = append(lines, d.formatBinding(binding, keyStyle, descStyle, contentWidth))
+		}
+		lines = append(lines, "")
+	}
+
+	// Render other bindings
+	if len(otherBindings) > 0 {
+		lines = append(lines, styles.DialogHelpStyle.Bold(true).Render("Other"))
+		lines = append(lines, "")
+		for _, binding := range otherBindings {
+			lines = append(lines, d.formatBinding(binding, keyStyle, descStyle, contentWidth))
+		}
+	}
+
+	return lines
+}
+
+// formatBinding formats a single key binding as "  key  description"
+func (d *helpDialog) formatBinding(binding key.Binding, keyStyle, descStyle lipgloss.Style, width int) string {
+	helpInfo := binding.Help()
+	helpKey := helpInfo.Key
+	helpDesc := helpInfo.Desc
+	
+	// Calculate spacing to align descriptions
+	const keyWidth = 20
+	const indent = 2
+	
+	keyPart := keyStyle.Render(helpKey)
+	descPart := descStyle.Render(helpDesc)
+	
+	// Pad the key part to align descriptions
+	keyPartWidth := lipgloss.Width(keyPart)
+	padding := strings.Repeat(" ", max(1, keyWidth-keyPartWidth))
+	
+	return fmt.Sprintf("%s%s%s%s", 
+		strings.Repeat(" ", indent),
+		keyPart,
+		padding,
+		descPart,
+	)
+}
+
+func (d *helpDialog) Init() tea.Cmd {
+	return d.readOnlyScrollDialog.Init()
+}
+
+func (d *helpDialog) Update(msg tea.Msg) (layout.Model, tea.Cmd) {
+	model, cmd := d.readOnlyScrollDialog.Update(msg)
+	if model != nil {
+		if rod, ok := model.(*readOnlyScrollDialog); ok {
+			d.readOnlyScrollDialog = *rod
+		}
+	}
+	return d, cmd
+}
+
+func (d *helpDialog) View() string {
+	return d.readOnlyScrollDialog.View()
+}
+
+func (d *helpDialog) Position() (int, int) {
+	return d.readOnlyScrollDialog.Position()
+}
+
+func (d *helpDialog) SetSize(width, height int) tea.Cmd {
+	return d.readOnlyScrollDialog.SetSize(width, height)
+}
+
+func (d *helpDialog) Bindings() []key.Binding {
+	return []key.Binding{}
+}

pkg/tui/tui.go

@@ -1687,6 +1687,12 @@ func (m *appModel) handleKeyPress(msg tea.KeyPressMsg) (tea.Model, tea.Cmd) {
 
 	case key.Matches(msg, key.NewBinding(key.WithKeys("ctrl+x"))):
 		return m, core.CmdHandler(messages.ClearQueueMsg{})
+
+	case key.Matches(msg, key.NewBinding(key.WithKeys("ctrl+?"))):
+		// Show contextual help dialog with all currently active key bindings
+		return m, core.CmdHandler(dialog.OpenDialogMsg{
+			Model: dialog.NewHelpDialog(m.Bindings()),
+		})
 	}
 
 	// History search is a modal state — capture all remaining keys before normal routing