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/store/migrations.go

@@ -16,7 +16,9 @@ import (
 //	var migrations = []string{
 //		`ALTER TABLE ...;`, // #1
 //	}
-var migrations = []string{}
+var migrations = []string{
+	`ALTER TABLE tools ADD COLUMN scope TEXT NOT NULL DEFAULT 'homelab';`,
+}
 
 // migrate applies every migration with a number greater than the DB's current
 // user_version, each in its own transaction that also bumps user_version. Fails