feat: introduce backend url environment variable

ref: N25B-352

src/pages/VisProgPage/VisProgLogic.ts

@@ -6,6 +6,7 @@ import orderPhaseNodeArray from "../../utils/orderPhaseNodes";
 import useFlowStore from './visualProgrammingUI/VisProgStores';
 import { NodeReduces } from './visualProgrammingUI/NodeRegistry';
 import type { PhaseNode } from "./visualProgrammingUI/nodes/PhaseNode";
+import { API_BASE_URL } from "../../config/api.ts";
 
 /**
  * Reduces the graph into its phases' information and recursively calls their reducing function
@@ -28,7 +29,7 @@ export function runProgram() {
   const program = {phases}
   console.log(JSON.stringify(program, null, 2));
   fetch(
-    "http://localhost:8000/program",
+    `${API_BASE_URL}/program`,
     {
       method: "POST",
       headers: {"Content-Type": "application/json"},
@@ -43,4 +44,4 @@ export function runProgram() {
     useProgramStore.getState().setProgramState(structuredClone(program));
   }).catch(() => console.log("Failed to send program to the backend."));
   console.log(program);
-}
+}