feat: initial gosleep-timer implementation

Go TUI sleep timer with modular architecture.
- Config: YAML-based, profile inheritance, auto WM detection
- Engine: timer, executor, stage pipeline (pre→timer→post)
- Modules: workspace (niri/hyprland/kde), media, lock, kill,
  notify, sound, brightness, mute, custom, script
- TUI: bubbletea app with profiles, module toggles, progress bar
- CLI: run, list-profiles, export, import, history, stats
- History: JSONL log with statistics
- QR: config export as ASCII QR

profiles/manager.go

@@ -0,0 +1,76 @@
+package profiles
+
+import (
+	"fmt"
+	"sort"
+
+	"github.com/forust/gosleep-timer/config"
+)
+
+type Manager struct {
+	cfg *config.Config
+}
+
+func NewManager(cfg *config.Config) *Manager {
+	return &Manager{cfg: cfg}
+}
+
+func (m *Manager) List() []string {
+	// Return sorted list of profile names
+	names := make([]string, 0, len(m.cfg.Profiles))
+	for name := range m.cfg.Profiles {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return names
+}
+
+func (m *Manager) Get(name string) (*config.Profile, error) {
+	p, ok := m.cfg.Profiles[name]
+	if !ok {
+		return nil, fmt.Errorf("profile %q not found", name)
+	}
+	return &p, nil
+}
+
+func (m *Manager) Info(name string) (*Info, error) {
+	p, err := m.Get(name)
+	if err != nil {
+		return nil, err
+	}
+	info := &Info{Name: name}
+	if p.Modules != nil {
+		m := p.Modules
+		if m.Workspace != nil && m.Workspace.Enabled {
+			info.Modules = append(info.Modules, "workspace")
+		}
+		if m.Media != nil && m.Media.Enabled {
+			info.Modules = append(info.Modules, "media")
+		}
+		if m.Lock != nil && m.Lock.Enabled {
+			info.Modules = append(info.Modules, "lock")
+		}
+		if m.Kill != nil && m.Kill.Enabled {
+			info.Modules = append(info.Modules, "kill")
+		}
+		if m.Notify != nil && m.Notify.Enabled {
+			info.Modules = append(info.Modules, "notify")
+		}
+		if m.Sound != nil && m.Sound.Enabled {
+			info.Modules = append(info.Modules, "sound")
+		}
+		if m.Brightness != nil && m.Brightness.Enabled {
+			info.Modules = append(info.Modules, "brightness")
+		}
+		if m.Mute != nil && m.Mute.Enabled {
+			info.Modules = append(info.Modules, "mute")
+		}
+		if m.Custom != nil && m.Custom.Enabled {
+			info.Modules = append(info.Modules, "custom")
+		}
+		if m.Script != nil && m.Script.Enabled {
+			info.Modules = append(info.Modules, "script")
+		}
+	}
+	return info, nil
+}