Fix restart policy from 'on-fail' to 'on-failure'

- Update case statement in internal/command/machine/run.go
- Update flag description to use correct policy name
- Update enum arrays in internal/command/mcp/server/machine.go
- Aligns with Docker restart policy standard and Machines API

Fixes #2844

Author: Fly Dev

internal/command/machine/run.go

@@ -126,8 +126,8 @@ var sharedFlags = flag.Set{
 	},
 	flag.String{
 		Name: "restart",
-		Description: `Set the restart policy for a Machine. Options include 'no', 'always', and 'on-fail'.
-	Default is 'on-fail' for Machines created by 'fly deploy' and Machines with a schedule. Default is 'always' for Machines created by 'fly m run'.`,
+		Description: `Set the restart policy for a Machine. Options include 'no', 'always', and 'on-failure'.
+	Default is 'on-failure' for Machines created by 'fly deploy' and Machines with a schedule. Default is 'always' for Machines created by 'fly m run'.`,
 	},
 	flag.StringSlice{
 		Name:        "standby-for",
@@ -780,7 +780,7 @@ func determineMachineConfig(
 		machineConf.Restart = &fly.MachineRestart{
 			Policy: fly.MachineRestartPolicyNo,
 		}
-	case "on-fail":
+	case "on-failure":
 		machineConf.Restart = &fly.MachineRestart{
 			Policy: fly.MachineRestartPolicyOnFailure,
 		}

internal/command/mcp/server/machine.go

@@ -309,7 +309,7 @@ var MachineCommands = []FlyCommand{
 				Description: "Restart policy for the new machine",
 				Required:    false,
 				Type:        "enum",
-				Enum:        []string{"no", "always", "on-fail"},
+				Enum:        []string{"no", "always", "on-failure"},
 			},
 			"rm": {
 				Description: "Automatically remove the Machine when it exits",
@@ -986,7 +986,7 @@ var MachineCommands = []FlyCommand{
 				Description: "Restart policy for the new machine",
 				Required:    false,
 				Type:        "enum",
-				Enum:        []string{"no", "always", "on-fail"},
+				Enum:        []string{"no", "always", "on-failure"},
 			},
 			"rm": {
 				Description: "Automatically remove the Machine when it exits",
@@ -1482,7 +1482,7 @@ var MachineCommands = []FlyCommand{
 				Description: "Restart policy for the new machine",
 				Required:    false,
 				Type:        "enum",
-				Enum:        []string{"no", "always", "on-fail"},
+				Enum:        []string{"no", "always", "on-failure"},
 			},
 			"schedule": {
 				Description: "Schedule for the new machine",