fs: move per-agent models to ctl command, remove models file

/models now lists available models for the agent's backend via ctl.
One fewer file in the agent namespace. The root-level models file
(all backends) remains unchanged.

data/scripts/o

@@ -33,7 +33,7 @@ ROOT_ENTRIES="session bypass agents backends models help ctl eventwait complete
 SESSION_FILES="env paused connected ctl name id bypass"
 
 # Agent-level files (exist under session/{name}/agent/{name}/)
-AGENT_FILES="prompt fifo chat chat.raw statewait log plan cfg ctl cwd stats models systemprompt tools name id proc"
+AGENT_FILES="prompt fifo chat chat.raw statewait log plan cfg ctl cwd stats systemprompt tools name id proc"
 
 is_root_path() {
     local path="$1"

fs/handlers.go

@@ -710,6 +710,8 @@ func requestAgentCtl(ctx HandlerCtx, data []byte) ([]byte, error) {
 			be.SetModel(strings.Join(args, " "))
 		}
 		return []byte(strings.Join(args, " ") + "\n"), nil
+	case "models":
+		return []byte(ctx.Session.CachedListModels() + "\n"), nil
 	case "backend":
 		if len(args) == 0 {
 			if be := ctx.Agent.Backend(); be != nil {
@@ -760,10 +762,6 @@ func readAgentStats(ctx HandlerCtx) ([]byte, error) {
 	return []byte(s), nil
 }
 
-func readAgentModels(ctx HandlerCtx) ([]byte, error) {
-	return []byte(ctx.Session.CachedListModels() + "\n"), nil
-}
-
 func readAgentSystemprompt(ctx HandlerCtx) ([]byte, error) {
 	return []byte(ctx.Agent.SystemPrompt() + "\n"), nil
 }

fs/spec.go

@@ -280,11 +280,6 @@ FileNode("generate", 0666,
 						Read(readAgentStats),
 					),
 
-					FileNode("models", 0444,
-						Doc("Available models for this agent's backend."),
-						Read(readAgentModels),
-					),
-
 					FileNode("systemprompt", 0444,
 						Doc("Fully rendered system prompt for this agent."),
 						Read(readAgentSystemprompt),