ci: run Build & Test on dev (push + PRs), not just main

Under the main=tags / dev=active model, build.yml only triggering on main meant PRs into dev got zero CI and bugs surfaced only at the dev->main release PR. Adding dev to the push/pull_request branch filters runs the same matrix (Node 22.x/24.x + bun unit tests) on every dev contribution.

Author: igorls

.github/workflows/build.yml

@@ -2,9 +2,9 @@ name: Build & Test
 
 on:
   push:
-    branches: [ "main" ]
+    branches: [ "main", "dev" ]
   pull_request:
-    branches: [ "main" ]
+    branches: [ "main", "dev" ]
 
 jobs:
   build: