tools: add scope column for capability model

Add a 'scope' TEXT column (default 'homelab') to the tools table so tools
can be namespaced by scope (e.g. "homelab:restart", "datacenter:reboot").
Backward-compat: bare name defaults to "homelab" scope.

Changes:
- Migration #1: ALTER TABLE tools ADD COLUMN scope
- store.Tool: add Scope field, update all SQL and scanTool()
- ipc.Tool DTO and request types: add Scope field
- CoreAPI interface: pass scope in ProposeTool/EnableTool
- storeAPI adapters: forward scope
- cmd/mavend/voice: pass scope (empty → homelab)
- cmd/mavweb/tools: show scope column in UI tables, hidden fields
- All tests updated for scope field
- Migration test made dynamic (startVer = len(migrations))

internal/config/config.go

@@ -180,6 +180,7 @@ type VoiceConfig struct {
 // must not fire from the voice path (they need a confirm on an authed surface).
 type ToolConfig struct {
 	Name        string   `json:"name"`
+	Scope       string   `json:"scope,omitempty"`
 	Cmd         []string `json:"cmd"`
 	Destructive bool     `json:"destructive,omitempty"`
 }