Add keyboard shortcuts help screen

- Created help.go with Screen interface implementation
- Help screen displays all shortcuts in two-column layout
- Categories: Navigation (j/k, arrows, Enter, Esc), Actions (a, d, D, Q, r, l), Other (?, /, q)
- Added '?' key handler in main.go to switch to help screen
- Help reference added to status bar
- Press q or Esc to return from help screen
- Styled with lipgloss for clear readability

internal/tui/screens/help.go

@@ -0,0 +1,112 @@
+package screens
+
+import (
+	"github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+)
+
+// HelpScreen displays keyboard shortcuts
+type HelpScreen struct {
+	previousScreen Screen
+}
+
+// NewHelpScreen creates a new help screen
+func NewHelpScreen(previous Screen) *HelpScreen {
+	return &HelpScreen{
+		previousScreen: previous,
+	}
+}
+
+// Init initializes the help screen
+func (s *HelpScreen) Init() tea.Cmd {
+	return nil
+}
+
+// Update handles messages for the help screen
+func (s *HelpScreen) Update(msg tea.Msg) (Screen, tea.Cmd) {
+	switch msg := msg.(type) {
+	case tea.KeyMsg:
+		switch msg.String() {
+		case "q", "esc":
+			// Return to previous screen
+			return s.previousScreen, nil
+		}
+	}
+	return s, nil
+}
+
+// View renders the help screen
+func (s *HelpScreen) View() string {
+	// Styles
+	borderStyle := lipgloss.NewStyle().
+		BorderStyle(lipgloss.RoundedBorder()).
+		BorderForeground(lipgloss.Color("62")).
+		Padding(1, 2)
+
+	headerStyle := lipgloss.NewStyle().
+		Foreground(lipgloss.Color("62")).
+		Bold(true).
+		MarginBottom(1)
+
+	categoryStyle := lipgloss.NewStyle().
+		Foreground(lipgloss.Color("226")).
+		Bold(true).
+		MarginTop(1).
+		MarginBottom(0)
+
+	keyStyle := lipgloss.NewStyle().
+		Foreground(lipgloss.Color("63")).
+		Bold(true).
+		Width(12)
+
+	descStyle := lipgloss.NewStyle().
+		Foreground(lipgloss.Color("250"))
+
+	// Header
+	header := headerStyle.Render("Keyboard Shortcuts")
+
+	// Shortcut groups
+	navigationGroup := categoryStyle.Render("Navigation") + "\n" +
+		keyStyle.Render("j / ↓") + descStyle.Render("Move down") + "\n" +
+		keyStyle.Render("k / ↑") + descStyle.Render("Move up") + "\n" +
+		keyStyle.Render("← →") + descStyle.Render("Move left/right") + "\n" +
+		keyStyle.Render("Enter") + descStyle.Render("Select") + "\n" +
+		keyStyle.Render("Esc") + descStyle.Render("Go back")
+
+	actionsGroup := categoryStyle.Render("Actions") + "\n" +
+		keyStyle.Render("a") + descStyle.Render("Add client") + "\n" +
+		keyStyle.Render("d") + descStyle.Render("Delete client") + "\n" +
+		keyStyle.Render("D") + descStyle.Render("Client details") + "\n" +
+		keyStyle.Render("Q") + descStyle.Render("Show QR code") + "\n" +
+		keyStyle.Render("r") + descStyle.Render("Refresh list") + "\n" +
+		keyStyle.Render("l") + descStyle.Render("List view")
+
+	otherGroup := categoryStyle.Render("Other") + "\n" +
+		keyStyle.Render("?") + descStyle.Render("Show this help") + "\n" +
+		keyStyle.Render("/") + descStyle.Render("Search") + "\n" +
+		keyStyle.Render("q") + descStyle.Render("Quit")
+
+	// Two-column layout
+	leftColumn := lipgloss.JoinVertical(lipgloss.Left,
+		navigationGroup,
+		"",
+		actionsGroup,
+	)
+
+	rightColumn := lipgloss.JoinVertical(lipgloss.Left,
+		otherGroup,
+	)
+
+	content := lipgloss.JoinHorizontal(lipgloss.Top, leftColumn, "  ", rightColumn)
+
+	// Footer
+	footerStyle := lipgloss.NewStyle().
+		Foreground(lipgloss.Color("241")).
+		MarginTop(1)
+	footer := footerStyle.Render("Press q or Esc to return")
+
+	// Combine all
+	return borderStyle.Render(
+		lipgloss.JoinVertical(lipgloss.Left, header, content, footer),
+	)
+}