[global] Turn on feature, keep command hidden (#622)

## Summary

Turns feature on. Adds warning if profile/bin path is not in $PATH

## How was it tested?

`devbox global add hello` 

<img width="1082" alt="image"
src="https://user-images.githubusercontent.com/544948/218209148-a168ac25-08f3-4e9a-ae36-a98508b062e8.png">

Author: mikeland73

internal/boxcli/featureflag/home.go

@@ -13,7 +13,6 @@ import (
 
 	"github.com/fatih/color"
 	"github.com/pkg/errors"
-	"go.jetpack.io/devbox/internal/boxcli/featureflag"
 	"go.jetpack.io/devbox/internal/boxcli/usererr"
 	"go.jetpack.io/devbox/internal/cuecfg"
 	"go.jetpack.io/devbox/internal/debug"
@@ -51,9 +50,6 @@ type Stage struct {
 var commitMismatchWarningShown = false
 
 func (c *Config) Packages(w io.Writer) []string {
-	if featureflag.Home.Disabled() {
-		return c.RawPackages
-	}
 	path, err := GlobalConfigPath()
 	if err != nil {
 		return c.RawPackages

internal/impl/config.go

@@ -12,6 +12,7 @@ import (
 	"github.com/fatih/color"
 	"github.com/pkg/errors"
 	"github.com/samber/lo"
+	"go.jetpack.io/devbox/internal/boxcli/usererr"
 	"go.jetpack.io/devbox/internal/nix"
 	"go.jetpack.io/devbox/internal/planner/plansdk"
 )
@@ -37,7 +38,10 @@ func (d *Devbox) AddGlobal(pkgs ...string) error {
 		}
 	}
 	d.cfg.RawPackages = lo.Uniq(append(d.cfg.RawPackages, added...))
-	return d.saveCfg()
+	if err := d.saveCfg(); err != nil {
+		return err
+	}
+	return ensureGlobalProfileInPath()
 }
 
 func (d *Devbox) RemoveGlobal(pkgs ...string) error {
@@ -90,3 +94,18 @@ func GlobalConfigPath() (string, error) {
 	}
 	return filepath.Join(home, "/.config/devbox/"), nil
 }
+
+// Checks if the global profile is in the path
+func ensureGlobalProfileInPath() error {
+	profilePath, err := globalProfilePath()
+	if err != nil {
+		return err
+	}
+	binPath := filepath.Join(profilePath, "bin")
+	if !strings.Contains(os.Getenv("PATH"), binPath) {
+		return usererr.NewWarning(
+			"devbox global profile is not in your PATH. Add `export PATH=$PATH:%s` to your shell config to fix this.", binPath,
+		)
+	}
+	return nil
+}