fix(kasmvnc): change installed check and bump default version (#505)

## Description

This PR makes the following changes to the `coder/modules/kasmvnc`:
- Change the installation check from checking `vncserver` to
`kasmvncserver`.
- Bump the default KasmVNC installation version to
[1.4.0](https://docs.kasmvnc.com/docs/release_notes/1.4.0).

In images where there is already TightVNC installed, the current
installation check will erroneously report that KasmVNC is already
installed. By checking `kasmvncserver` instead, it ensures KasmVNC is
installed.

Tested on Debian, Kali and Alpine-based images.

## Type of Change

- [ ] New module
- [ ] New template
- [X] Bug fix
- [ ] Feature/enhancement
- [ ] Documentation
- [ ] Other

## Module Information

**Path:** `registry/coder/modules/kasmvnc`  
**New version:** `v1.2.5`  
**Breaking change:** [ ] Yes [X] No

## Testing & Validation

- [X] Tests pass (`bun test`)
- [X] Code formatted (`bun fmt`)
- [X] Changes tested locally

## Related Issues

None

registry/coder/modules/kasmvnc/README.md

@@ -14,7 +14,7 @@ Automatically install [KasmVNC](https://kasmweb.com/kasmvnc) in a workspace, and
 module "kasmvnc" {
   count               = data.coder_workspace.me.start_count
   source              = "registry.coder.com/coder/kasmvnc/coder"
-  version             = "1.2.4"
+  version             = "1.2.5"
   agent_id            = coder_agent.example.id
   desktop_environment = "xfce"
   subdomain           = true

registry/coder/modules/kasmvnc/main.tf

@@ -23,7 +23,7 @@ variable "port" {
 variable "kasm_version" {
   type        = string
   description = "Version of KasmVNC to install."
-  default     = "1.3.2"
+  default     = "1.4.0"
 }
 
 variable "desktop_environment" {

registry/coder/modules/kasmvnc/run.sh

@@ -8,10 +8,10 @@ error() {
   exit 1
 }
 
-# Function to check if vncserver is already installed
+# Function to check if KasmVNC is already installed
 check_installed() {
-  if command -v vncserver &> /dev/null; then
-    echo "vncserver is already installed."
+  if command -v kasmvncserver &> /dev/null; then
+    echo "KasmVNC is already installed."
     return 0 # Don't exit, just indicate it's installed
   else
     return 1 # Indicates not installed
@@ -158,7 +158,7 @@ case "$arch" in
     ;;
 esac
 
-# Check if vncserver is installed, and install if not
+# Check if KasmVNC is installed, and install if not
 if ! check_installed; then
   # Check for NOPASSWD sudo (required)
   if ! command -v sudo &> /dev/null || ! sudo -n true 2> /dev/null; then
@@ -188,7 +188,7 @@ if ! check_installed; then
       ;;
   esac
 else
-  echo "vncserver already installed. Skipping installation."
+  echo "KasmVNC already installed. Skipping installation."
 fi
 
 if command -v sudo &> /dev/null && sudo -n true 2> /dev/null; then
@@ -227,7 +227,7 @@ EOF
 # This password is not used since we start the server without auth.
 # The server is protected via the Coder session token / tunnel
 # and does not listen publicly
-echo -e "password\npassword\n" | vncpasswd -wo -u "$USER"
+echo -e "password\npassword\n" | kasmvncpasswd -wo -u "$USER"
 
 get_http_dir() {
   # determine the served file path
@@ -290,7 +290,7 @@ VNC_LOG="/tmp/kasmvncserver.log"
 printf "🚀 Starting KasmVNC server...\n"
 
 set +e
-vncserver -select-de "${DESKTOP_ENVIRONMENT}" -disableBasicAuth > "$VNC_LOG" 2>&1
+kasmvncserver -select-de "${DESKTOP_ENVIRONMENT}" -disableBasicAuth > "$VNC_LOG" 2>&1
 RETVAL=$?
 set -e