refactor: remove core skill direct loading, skills owned by clawhubadapter only

- Drop skill.NewManager from homed bootstrap; skills dir no longer core-managed
- Remove GetInjectedPrompt system-prompt injection (skills are not first-class)
- Delete internal/skill package, SkillAPI, webui /api/v1/skills, status skills block
- ConfigRegistry: plugin config tables now created only via RegisterDef; arbitrary
  scope Set/Get no longer implicitly creates config_<name> tables (fixes stray
  config_today_task table from SKILL directory name being used as a scope)

internal/sdk/plugin.go

@@ -90,7 +90,6 @@ type PluginSDK struct {
 
 	status     StatusAPI
 	supervisor SupervisorAPI
-	skill      SkillAPI
 	adapter    AdapterAPI
 	tracker    TrackerAPI
 	config     ConfigAPI
@@ -150,7 +149,6 @@ type SDKConfig struct {
 
 	Status     StatusAPI
 	Supervisor SupervisorAPI
-	Skill      SkillAPI
 	Adapter    AdapterAPI
 	Tracker    TrackerAPI
 	Config     ConfigAPI
@@ -187,7 +185,6 @@ func New(name string, cfg SDKConfig) *PluginSDK {
 
 		status:     cfg.Status,
 		supervisor: cfg.Supervisor,
-		skill:      cfg.Skill,
 		adapter:    cfg.Adapter,
 		tracker:    cfg.Tracker,
 		config:     cfg.Config,
@@ -198,7 +195,6 @@ func New(name string, cfg SDKConfig) *PluginSDK {
 
 func (s *PluginSDK) Status() StatusAPI        { return s.status }
 func (s *PluginSDK) Supervisor() SupervisorAPI { return s.supervisor }
-func (s *PluginSDK) Skill() SkillAPI          { return s.skill }
 func (s *PluginSDK) Adapter() AdapterAPI      { return s.adapter }
 func (s *PluginSDK) Tracker() TrackerAPI      { return s.tracker }
 func (s *PluginSDK) Config() ConfigAPI        { return s.config }

internal/sdk/skill.go

@@ -1,22 +0,0 @@
-package sdk
-
-// SkillAPI provides access to the skill manager.
-type SkillAPI interface {
-	List() []*Skill
-	Get(name string) *Skill
-	Install(name, content string) error
-	Uninstall(name string) error
-	Toggle(name string, enabled bool) error
-}
-
-// Skill is a neutral description of an installed skill.
-type Skill struct {
-	Name        string `json:"name"`
-	Description string `json:"description"`
-	Version     string `json:"version"`
-	Author      string `json:"author,omitempty"`
-	Entry       string `json:"entry,omitempty"`
-	Source      string `json:"source,omitempty"`
-	Enabled     bool   `json:"enabled"`
-	RawContent  string `json:"-"`
-}

internal/sdk/status.go

@@ -21,7 +21,6 @@ type KernelStatus struct {
 	Documents  DocumentStatus   `json:"documents"`
 	TextMemory TextMemoryStatus `json:"text_memory"`
 	Social     SocialStatus     `json:"social"`
-	Skills     SkillsStatus     `json:"skills"`
 
 	LLM LLMStatus `json:"llm"`
 
@@ -72,11 +71,6 @@ type SocialStatus struct {
 	PersonCount int  `json:"person_count"`
 }
 
-type SkillsStatus struct {
-	Available bool     `json:"available"`
-	SkillList []string `json:"skill_list,omitempty"`
-}
-
 type LLMStatus struct {
 	Available bool   `json:"available"`
 	Provider  string `json:"provider,omitempty"`