chore: add bunfig.toml and update gitignore for test config

- add bunfig.toml to scope bun test to ./tests/ only
- add ui test output directory to gitignore
- separates main (bun test) and UI (vitest) test runners

.gitignore

@@ -38,4 +38,7 @@ package-lock.json
 logs/
 
 # CI-generated files
-.dev-release-info.json
+.dev-release-info.json
+
+# Test coverage
+ui/coverage/

bunfig.toml

@@ -0,0 +1,4 @@
+[test]
+# Exclude UI tests - they use vitest and require jsdom environment
+# Run UI tests separately with: cd ui && bun run test
+root = "./tests"