Set up environment-based configurations for API and builds.

Replaced hardcoded API URLs with environment-specific configurations. Added new environments (development, beta, production) with respective settings. Updated build scripts and Angular file replacements to support environment-based builds.

frontend/src/environments/environment.beta.ts

@@ -0,0 +1,4 @@
+export const environment = {
+  production: true,
+  apiUrl: 'https://beta.alttd.com'
+};

frontend/src/environments/environment.development.ts

@@ -0,0 +1,4 @@
+export const environment = {
+  production: false,
+  apiUrl: 'http://localhost:8080'
+};

frontend/src/environments/environment.production.ts

@@ -0,0 +1,4 @@
+export const environment = {
+  production: true,
+  apiUrl: 'https://alttd.com'
+};

frontend/src/environments/environment.ts

@@ -0,0 +1,4 @@
+export const environment = {
+  production: true,
+  apiUrl: 'https://alttd.com'
+};