test: pass node --test an explicit file list (Node 22 no longer expands directories)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Makefile

@@ -31,7 +31,7 @@ lint: node_modules/.package-lock.json
 	jq empty share/claude-settings.json
 
 test: node_modules/.package-lock.json
-	node --test tests/
+	node --test tests/*.test.mjs
 	bats tests/
 
 install: all

package.json

@@ -8,7 +8,7 @@
   "scripts": {
     "build": "node web/build.mjs",
     "lint": "eslint --ext .js,.mjs web/src web/build.mjs tests/protocol.test.mjs",
-    "test": "node --test tests/"
+    "test": "node --test tests/*.test.mjs"
   },
   "devDependencies": {
     "@fontsource/jetbrains-mono": "5.3.0",