fix: accept response code 422 in htmx as 'should swap'

assets/app.js

@@ -13,3 +13,12 @@ htmx.config.allowScriptTags = false
 htmx.config.withCredentials = true
 htmx.config.selfRequestsOnly = false
 htmx.config.timeout = 50000 // 50 seconds - slightly higher than backend timeout (45s)
+
+document.body.addEventListener('htmx:beforeSwap', (event) => {
+    // Symfony renders invalid forms with 422; let HTMX swap those responses so inline
+    // validation errors are actually shown to the user.
+    if (event.detail?.xhr?.status === 422) {
+        event.detail.shouldSwap = true
+        event.detail.isError = false
+    }
+})