Add server-side workflows with YAML files, task freeze and lead tools

internal/agents/lead.go

@@ -11,6 +11,7 @@ import (
 
 	"g.fc.run/misc/byre/internal/api"
 	"g.fc.run/misc/byre/internal/store"
+	"g.fc.run/misc/byre/internal/workflow"
 )
 
 const leadGuidance = `You are the human's lead agent in byre, shown in the left pane of byre's web UI. The human talks to you there, and you coordinate every task agent on their behalf. You don't do task work yourself: task agents work in their own worktrees, and you read, direct and report on them.
@@ -67,7 +68,7 @@ func (m *Manager) createLead(ctx context.Context, owner api.User, prompt, model,
 	}
 
 	id := newUUID()
-	vendor := vendorOf(model)
+	vendor := workflow.VendorOf(model)
 	sess := api.AgentSession{
 		Id:              id,
 		Owner:           owner.Login,