docs(goose): update README to include tmux as an alternative to screen and session name variable

Author: DevelopmentCats

registry/coder/modules/goose/README.md

@@ -24,14 +24,14 @@ module "goose" {
 
 ## Prerequisites
 
-- `screen` must be installed in your workspace to run Goose in the background
+- `screen` or `tmux` must be installed in your workspace to run Goose in the background
 - You must add the [Coder Login](https://registry.coder.com/modules/coder-login) module to your template
 
 The `codercom/oss-dogfood:latest` container image can be used for testing on container-based workspaces.
 
 ## Examples
 
-Your workspace must have `screen` installed to use this.
+Your workspace must have `screen` or `tmux` installed to use the background session functionality.
 
 ### Run in the background and report tasks (Experimental)
 
@@ -99,8 +99,12 @@ module "goose" {
   # Enable experimental features
   experiment_report_tasks = true
 
-  # Run Goose in the background
+  # Run Goose in the background with screen (pick one: screen or tmux)
   experiment_use_screen = true
+  # experiment_use_tmux = true  # Alternative: use tmux instead of screen
+
+  # Optional: customize the session name (defaults to "goose")
+  # session_name = "goose-session"
 
   # Avoid configuring Goose manually
   experiment_auto_configure = true
@@ -143,7 +147,7 @@ Note: The indentation in the heredoc is preserved, so you can write the YAML nat
 
 ## Run standalone
 
-Run Goose as a standalone app in your workspace. This will install Goose and run it directly without using screen or any task reporting to the Coder UI.
+Run Goose as a standalone app in your workspace. This will install Goose and run it directly without using screen or tmux, and without any task reporting to the Coder UI.
 
 ```tf
 module "goose" {