Panels dialog saves a ready I/O port draft on close and keeps an unfinished one; one qualified message-name rule on both sides

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WgBfkm4rCmtd1T4vHWjEPx

frontend/src/components/Flow/deriveEdges.ts

@@ -8,6 +8,19 @@ export function qualify(flow: string, name: string): string {
   return name.includes(".") ? name : `${flow}.${name}`
 }
 
+/**
+ * A message named with its flow, as the server checks it wherever a name has
+ * to arrive qualified (`QUALIFIED_PATTERN` in `flow/messages.py`).
+ */
+const QUALIFIED_MESSAGE = /^[a-z][a-z0-9_]*(\.[A-Za-z0-9_]+)+$/
+
+/** What is wrong with a name that has to be qualified, or null. */
+export function qualifiedProblem(name: string): string | null {
+  return QUALIFIED_MESSAGE.test(name)
+    ? null
+    : "Name the message as flow.name: a lowercase flow name, a dot, then letters, digits and underscores"
+}
+
 /** The flow a qualified message belongs to. */
 export function flowOf(message: string): string {
   return message.split(".", 1)[0]