fix(vscode-web): apply settings on every workspace start

Previously, settings were only written to settings.json if the file
did not already exist. This meant that template changes to the settings
variable would never be applied to existing workspaces.

Now, Machine settings are always applied on every workspace start,
which is the expected behavior for template-controlled settings.

Fixes: https://github.com/coder/registry/issues/42

registry/coder/modules/vscode-web/README.md

@@ -53,7 +53,7 @@ module "vscode-web" {
 
 ### Pre-configure Settings
 
-Configure VS Code's [settings.json](https://code.visualstudio.com/docs/getstarted/settings#_settings-json-file) file:
+Configure VS Code's [Machine settings.json](https://code.visualstudio.com/docs/getstarted/settings#_settings-json-file) file. These settings are applied on every workspace start, ensuring template-defined settings are always enforced:
 
 ```tf
 module "vscode-web" {

registry/coder/modules/vscode-web/run.sh

@@ -28,12 +28,12 @@ run_vscode_web() {
   "$VSCODE_WEB" serve-local "$EXTENSION_ARG" "$SERVER_BASE_PATH_ARG" "$DISABLE_TRUST_ARG" --port "${PORT}" --host 127.0.0.1 --accept-server-license-terms --without-connection-token --telemetry-level "${TELEMETRY_LEVEL}" > "${LOG_PATH}" 2>&1 &
 }
 
-# Check if the settings file exists...
-if [ ! -f ~/.vscode-server/data/Machine/settings.json ]; then
-  echo "⚙️ Creating settings file..."
+# Apply/overwrite template-based settings on every start
+# Machine settings are always overwritten to apply template changes.
+# See: https://github.com/coder/registry/issues/42
+echo "⚙️ Applying VS Code settings..."
 mkdir -p ~/.vscode-server/data/Machine
 echo "${SETTINGS}" > ~/.vscode-server/data/Machine/settings.json
-fi
 
 # Check if vscode-server is already installed for offline or cached mode
 if [ -f "$VSCODE_WEB" ]; then