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

config/types.go

@@ -0,0 +1,74 @@
+package config
+
+type Config struct {
+	Profiles map[string]Profile `yaml:"profiles"`
+}
+
+type Profile struct {
+	Extends string   `yaml:"extends,omitempty"`
+	Modules *Modules `yaml:"modules,omitempty"`
+}
+
+type Modules struct {
+	Workspace  *WorkspaceConfig  `yaml:"workspace,omitempty"`
+	Media      *MediaConfig      `yaml:"media,omitempty"`
+	Lock       *LockConfig       `yaml:"lock,omitempty"`
+	Kill       *KillConfig       `yaml:"kill,omitempty"`
+	Notify     *NotifyConfig     `yaml:"notify,omitempty"`
+	Sound      *SoundConfig      `yaml:"sound,omitempty"`
+	Brightness *BrightnessConfig `yaml:"brightness,omitempty"`
+	Mute       *MuteConfig       `yaml:"mute,omitempty"`
+	Custom     *CustomConfig     `yaml:"custom,omitempty"`
+	Script     *ScriptConfig     `yaml:"script,omitempty"`
+}
+
+type WorkspaceConfig struct {
+	Enabled   bool   `yaml:"enabled" default:"true"`
+	Backend   string `yaml:"backend"` // auto, niri, hyprland, kde
+	Workspace int    `yaml:"workspace"`
+}
+
+type MediaConfig struct {
+	Enabled bool   `yaml:"enabled" default:"true"`
+	Action  string `yaml:"action"` // stop, pause, play-pause, next, previous, none
+}
+
+type LockConfig struct {
+	Enabled bool   `yaml:"enabled" default:"true"`
+	Command string `yaml:"command"` // custom lock cmd, empty = auto
+}
+
+type KillConfig struct {
+	Enabled   bool     `yaml:"enabled" default:"false"`
+	Processes []string `yaml:"processes"`
+}
+
+type NotifyConfig struct {
+	Enabled bool   `yaml:"enabled" default:"true"`
+	Sound   string `yaml:"sound"` // path or empty
+}
+
+type SoundConfig struct {
+	Enabled bool   `yaml:"enabled" default:"true"`
+	File    string `yaml:"file"`
+}
+
+type BrightnessConfig struct {
+	Enabled bool `yaml:"enabled" default:"false"`
+	Value   int  `yaml:"value"` // 0-100
+}
+
+type MuteConfig struct {
+	Enabled bool `yaml:"enabled" default:"false"`
+}
+
+type CustomConfig struct {
+	Enabled bool     `yaml:"enabled" default:"false"`
+	Pre     []string `yaml:"pre"`
+	Post    []string `yaml:"post"`
+}
+
+type ScriptConfig struct {
+	Enabled bool   `yaml:"enabled" default:"false"`
+	Path    string `yaml:"path"`
+}