feat(tui): add jump component for navigation by steps

- add `Jump` struct with number input and directional navigation
- support vim-style (`h`/`l`) and arrow key navigation controls
- include visual overlay with input display and help text
- handle escape and ctrl+c for canceling jump operation

Author: tharropoulos

internal/tui/jump.go

@@ -0,0 +1,143 @@
+package tui
+
+import (
+	"strconv"
+
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+)
+
+type Jump struct {
+	numberInput string
+	jumpSteps   int
+	quitting    bool
+	showing     bool
+	width       int
+	height      int
+}
+
+func NewJump() Jump {
+	return Jump{
+		numberInput: "",
+		showing:     false,
+	}
+}
+
+func (m Jump) Init() tea.Cmd {
+	return nil
+}
+
+func (m Jump) Update(msg tea.Msg) (Jump, tea.Cmd) {
+	switch msg := msg.(type) {
+	case tea.WindowSizeMsg:
+		m.width = msg.Width
+		m.height = msg.Height
+		return m, nil
+	case tea.KeyMsg:
+		switch msg.String() {
+		case "esc", "ctrl+c":
+			m.quitting = true
+			m.showing = false
+			return m, nil
+		case "1", "2", "3", "4", "5", "6", "7", "8", "9":
+			if len(m.numberInput) < 4 {
+				m.numberInput += msg.String()
+			}
+			return m, nil
+		case "backspace":
+			if len(m.numberInput) > 0 {
+				m.numberInput = m.numberInput[:len(m.numberInput)-1]
+			}
+			return m, nil
+		case "h", "left":
+			if m.numberInput != "" {
+				if steps, err := strconv.Atoi(m.numberInput); err == nil {
+					m.jumpSteps = -steps
+				}
+				m.quitting = true
+				m.showing = false
+				return m, tea.Quit
+			}
+			return m, nil
+		case "l", "right":
+			if m.numberInput != "" {
+				if steps, err := strconv.Atoi(m.numberInput); err == nil {
+					m.jumpSteps = steps
+				}
+				m.quitting = true
+				m.showing = false
+				return m, tea.Quit
+			}
+			return m, nil
+		}
+	}
+	return m, nil
+}
+
+func (m Jump) Show(slideView string, width, height int) string {
+	displayNumber := m.numberInput
+	if displayNumber == "" {
+		displayNumber = "_"
+	}
+
+	statusContent := lipgloss.NewStyle().
+		Background(lipgloss.Color("#3C3C3C")).
+		Foreground(lipgloss.Color("#DDDDDD")).
+		Padding(0, 1).
+		Render(displayNumber)
+
+	statusWidth := lipgloss.Width(statusContent)
+	statusX := (width - statusWidth) / 2
+	statusY := height - 1
+
+	leftHelp := lipgloss.JoinHorizontal(
+		lipgloss.Center,
+		mutedStyle.Render("←/h"),
+		" ",
+		veryMutedStyle.Render("• previous"),
+	)
+
+	rightHelp := lipgloss.JoinHorizontal(
+		lipgloss.Center,
+		mutedStyle.Render("→/l"),
+		" ",
+		veryMutedStyle.Render("• next"),
+	)
+
+	escHelp := lipgloss.JoinHorizontal(
+		lipgloss.Center,
+		mutedStyle.Render("esc/ctrl+c"),
+		" ",
+		veryMutedStyle.Render("• cancel"),
+	)
+
+	helpText := lipgloss.JoinHorizontal(lipgloss.Center, leftHelp, "  ", rightHelp, "  ", escHelp)
+	helpWidth := lipgloss.Width(helpText)
+	helpX := (width - helpWidth) / 2
+	helpY := height - 3
+
+	viewWithStatus := placeOverlay(statusX, statusY, statusContent, slideView)
+	return placeOverlay(helpX, helpY, helpText, viewWithStatus)
+}
+
+func (m Jump) IsShowing() bool {
+	return m.showing
+}
+
+func (m Jump) SetShowing(showing bool) Jump {
+	m.showing = showing
+	if showing {
+		m.numberInput = ""
+		m.jumpSteps = 0
+		m.quitting = false
+	}
+	return m
+}
+
+func (m Jump) Quitting() bool {
+	return m.quitting
+}
+
+func (m Jump) JumpSteps() int {
+	return m.jumpSteps
+}