refactor: merge Install and InstallLocalApp into a single function

The Install (slack deploy) and InstallLocalApp (slack run) functions in
internal/pkg/apps were ~90% identical. Collapse them into one Install
function driven by a dev bool toggle.

- dev switches display name, hosted manifest defaults, persistence
  (SaveLocal vs SaveDeployed), IsDev, and env-token handling.
- Drop the dead onlyCreateUpdateAppManifest parameter and its
  CreateAppManifestOnly/CreateAppManifestAndInstall constants; nothing
  passed CreateAppManifestOnly, so the early-return branch was unreachable.
- Unify accidental gaps: both paths now set EnterpriseID and UserID on
  new-app creation inside nil guards (deploy previously left these as
  TODOs; local dereferenced UserID unconditionally). Enterprise ID is
  also now correctly propagated on the context for the deploy path.
- Return the superset (App, DeveloperAppInstallResult, InstallState,
  error); only the dev path consumes the result (socket-mode wiring).

Update the three callers (add.go, run.go, localserver.go) and the
cmd/app func var to the merged signature.

Author: zimeg

cmd/app/add.go

@@ -32,7 +32,7 @@ import (
 // Handle to client's function used for testing
 var runAddCommandFunc = RunAddCommand
 var appInstallProdAppFunc = apps.Add
-var appInstallDevAppFunc = apps.InstallLocalApp
+var appInstallDevAppFunc = apps.Install
 var appSelectPromptFunc = prompts.AppSelectPrompt
 
 // Flags
@@ -201,7 +201,7 @@ func printAddSuccess(clients *shared.ClientFactory, cmd *cobra.Command, appInsta
 func appInstall(ctx context.Context, clients *shared.ClientFactory, selection *prompts.SelectedApp, orgGrantWorkspaceID string) (types.App, types.InstallState, error) {
 	if selection != nil && selection.App.IsDev {
 		// Install local dev app to a team
-		installedApp, _, installState, err := appInstallDevAppFunc(ctx, clients, "", selection.Auth, selection.App)
+		installedApp, _, installState, err := appInstallDevAppFunc(ctx, clients, selection.Auth, selection.App, "", true)
 		return installedApp, installState, err
 	} else {
 		installState, installedApp, err := appInstallProdAppFunc(ctx, clients, selection.Auth, selection.App, orgGrantWorkspaceID)

internal/pkg/apps/add.go

@@ -70,7 +70,7 @@ func addAppRemotely(ctx context.Context, clients *shared.ClientFactory, auth typ
 		app.TeamID = auth.TeamID
 	}
 
-	app, installState, err := Install(ctx, clients, auth, CreateAppManifestAndInstall, app, orgGrantWorkspaceID)
+	app, _, installState, err := Install(ctx, clients, auth, app, orgGrantWorkspaceID, false)
 	if err != nil {
 		return installState, types.App{}, slackerror.Wrap(err, slackerror.ErrAppAdd)
 	}