Add unit tests for channel utilities and configure testing environment

- Created a new test file `channels.test.ts` to cover utilities related to channel configurations and targets.
- Implemented tests for normalizing and grouping selected channels by type, as well as building channel targets from account data and cron history.
- Mocked necessary dependencies to isolate tests and ensure accurate results.
- Updated `vite.config.ts` to set up the testing environment with jsdom and enable global variables for tests.

vite.config.ts

@@ -115,6 +115,11 @@ export default defineConfig(({ mode }) => {
       renderer(),
     ],
 
+    test: {
+      environment: 'jsdom',
+      globals: true,
+    },
+
     css: {
       transformer: 'lightningcss',
     },