Feature: Interactive CPU workload selection in TUI menu

Added interactive workload type selector similar to database type selector:

- Three workload options: Balanced | CPU-Intensive | I/O-Intensive
- Switch with Shift+←/→ arrows or 'w' key
- Automatically adjusts Jobs and DumpJobs based on selection:
  * CPU-Intensive: More parallelism (2x physical cores)
  * I/O-Intensive: Less parallelism (0.5x physical cores)
  * Balanced: Standard parallelism (1x physical cores)

UI shows current selection with description:
- Balanced (General purpose)
- CPU-Intensive (More parallelism)
- I/O-Intensive (Less parallelism)

Real-time feedback shows adjusted Jobs/DumpJobs values.
Complements existing --cpu-workload CLI flag with interactive UX.

internal/tui/menu.go

@@ -48,6 +48,12 @@ type dbTypeOption struct {
 	value string
 }
 
+type workloadOption struct {
+	label string
+	value string
+	desc  string
+}
+
 // MenuModel represents the simple menu state
 type MenuModel struct {
 	choices         []string
@@ -58,6 +64,8 @@ type MenuModel struct {
 	message         string
 	dbTypes         []dbTypeOption
 	dbTypeCursor    int
+	workloads       []workloadOption
+	workloadCursor  int
 
 	// Background operations
 	ctx    context.Context
@@ -73,6 +81,12 @@ func NewMenuModel(cfg *config.Config, log logger.Logger) MenuModel {
 		{label: "MariaDB", value: "mariadb"},
 	}
 
+	workloads := []workloadOption{
+		{label: "Balanced", value: "balanced", desc: "General purpose"},
+		{label: "CPU-Intensive", value: "cpu-intensive", desc: "More parallelism"},
+		{label: "I/O-Intensive", value: "io-intensive", desc: "Less parallelism"},
+	}
+
 	dbCursor := 0
 	if cfg.DatabaseType == "mysql" {
 		dbCursor = 1
@@ -80,6 +94,13 @@ func NewMenuModel(cfg *config.Config, log logger.Logger) MenuModel {
 		dbCursor = 2
 	}
 
+	workloadCursor := 0
+	if cfg.CPUWorkloadType == "cpu-intensive" {
+		workloadCursor = 1
+	} else if cfg.CPUWorkloadType == "io-intensive" {
+		workloadCursor = 2
+	}
+
 	model := MenuModel{
 		choices: []string{
 			"Single Database Backup",
@@ -103,6 +124,8 @@ func NewMenuModel(cfg *config.Config, log logger.Logger) MenuModel {
 		cancel:         cancel,
 		dbTypes:        dbTypes,
 		dbTypeCursor:   dbCursor,
+		workloads:      workloads,
+		workloadCursor: workloadCursor,
 	}
 
 	return model
@@ -143,6 +166,24 @@ func (m MenuModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 				m.applyDatabaseSelection()
 			}
 
+		case "shift+left", "H":
+			if m.workloadCursor > 0 {
+				m.workloadCursor--
+				m.applyWorkloadSelection()
+			}
+
+		case "shift+right", "L":
+			if m.workloadCursor < len(m.workloads)-1 {
+				m.workloadCursor++
+				m.applyWorkloadSelection()
+			}
+
+		case "w":
+			if len(m.workloads) > 0 {
+				m.workloadCursor = (m.workloadCursor + 1) % len(m.workloads)
+				m.applyWorkloadSelection()
+			}
+
 		case "up", "k":
 			if m.cursor > 0 {
 				m.cursor--
@@ -218,6 +259,21 @@ func (m MenuModel) View() string {
 		selector := fmt.Sprintf("Target Engine: %s", strings.Join(options, menuStyle.Render("  |  ")))
 		s += dbSelectorLabelStyle.Render(selector) + "\n"
 		hint := infoStyle.Render("Switch with ←/→ or t • Cluster backup requires PostgreSQL")
+		s += hint + "\n"
+	}
+
+	if len(m.workloads) > 0 {
+		options := make([]string, len(m.workloads))
+		for i, opt := range m.workloads {
+			if m.workloadCursor == i {
+				options[i] = menuSelectedStyle.Render(fmt.Sprintf("%s (%s)", opt.label, opt.desc))
+			} else {
+				options[i] = menuStyle.Render(opt.label)
+			}
+		}
+		selector := fmt.Sprintf("CPU Workload: %s", strings.Join(options, menuStyle.Render("  |  ")))
+		s += dbSelectorLabelStyle.Render(selector) + "\n"
+		hint := infoStyle.Render("Switch with Shift+←/→ or w • Affects parallelism and compression")
 		s += hint + "\n\n"
 	}
 
@@ -346,6 +402,52 @@ func (m *MenuModel) applyDatabaseSelection() {
 	}
 }
 
+// applyWorkloadSelection updates the config with the selected workload type
+func (m *MenuModel) applyWorkloadSelection() {
+	if m.config == nil {
+		return
+	}
+	if m.workloadCursor < 0 || m.workloadCursor >= len(m.workloads) {
+		return
+	}
+
+	selection := m.workloads[m.workloadCursor]
+	m.config.CPUWorkloadType = selection.value
+
+	// Recalculate optimal settings based on workload type
+	if m.config.CPUInfo != nil && m.config.AutoDetectCores {
+		// Recalculate Jobs and DumpJobs based on new workload type
+		switch selection.value {
+		case "cpu-intensive":
+			// More parallelism for CPU-bound tasks
+			m.config.Jobs = m.config.CPUInfo.PhysicalCores * 2
+			m.config.DumpJobs = m.config.CPUInfo.PhysicalCores
+		case "io-intensive":
+			// Less parallelism to avoid I/O contention
+			m.config.Jobs = m.config.CPUInfo.PhysicalCores / 2
+			if m.config.Jobs < 1 {
+				m.config.Jobs = 1
+			}
+			m.config.DumpJobs = 2
+		default: // balanced
+			m.config.Jobs = m.config.CPUInfo.PhysicalCores
+			m.config.DumpJobs = m.config.CPUInfo.PhysicalCores / 2
+			if m.config.DumpJobs < 2 {
+				m.config.DumpJobs = 2
+			}
+		}
+	}
+
+	m.message = successStyle.Render(fmt.Sprintf("⚡ CPU workload set to %s (Jobs: %d, DumpJobs: %d)", 
+		selection.label, m.config.Jobs, m.config.DumpJobs))
+	if m.logger != nil {
+		m.logger.Info("updated CPU workload type", 
+			"type", m.config.CPUWorkloadType, 
+			"jobs", m.config.Jobs, 
+			"dump_jobs", m.config.DumpJobs)
+	}
+}
+
 // RunInteractiveMenu starts the simple TUI
 func RunInteractiveMenu(cfg *config.Config, log logger.Logger) error {
 	m := NewMenuModel(cfg, log)