Add Terraform variables for Azure resources

Define variables for resource group, location, name prefix, user principal ID, and Cosmos DB local auth.

Author: brown9804

terraform-infrastructure/variables.tf

@@ -0,0 +1,28 @@
+variable "resource_group_name" {
+  type        = string
+  description = "Existing resource group name where resources will be deployed"
+}
+
+variable "location" {
+  type        = string
+  description = "Azure region for resources"
+  default     = "eastus"
+}
+
+variable "name_prefix" {
+  type        = string
+  description = "Prefix for all resource names (will append random suffix)"
+  default     = "zava"
+}
+
+variable "user_principal_id" {
+  type        = string
+  description = "Object ID of the user/principal to grant Cosmos DB data contributor access. Defaults to current Azure CLI user."
+  default     = null
+}
+
+variable "enable_cosmos_local_auth" {
+  type        = bool
+  description = "Whether to enable local auth on Cosmos DB account"
+  default     = true
+}