Added AI generated scaffold.

variables.tf

@@ -0,0 +1,15 @@
+variable "project_id" {
+  description = "The ID of the existing GCP project to scaffold into."
+  type        = string
+}
+
+variable "prefix" {
+  description = "Short name prefix applied to all created resource names."
+  type        = string
+  default     = "gemini"
+
+  validation {
+    condition     = can(regex("^[a-z][a-z0-9-]{0,14}$", var.prefix))
+    error_message = "prefix must be 1-15 lowercase letters, digits, or hyphens, starting with a letter."
+  }
+}