UI: pick a stable, project-unique dev port (5180 -> 7788)

`sha1('disk-tree') % 6000 + 4000` keeps per-project ports out of the
crowded 5xxx range so concurrent dev servers don't collide.

Author: ryan-williams

ui/vite.config.ts

@@ -6,7 +6,8 @@ export default defineConfig({
   plugins: [react()],
 
   server: {
-    port: 5180,
+    // sha1('disk-tree') % 6000 + 4000
+    port: 7788,
     strictPort: true,  // Exit with error if port is already in use
     proxy: {
       '/api': {