fix(debugger): finish PHP Remote Debug: taken port, waiting state, Port field (#1639)

A taken port now says which port is in use instead of Node's EADDRINUSE text; a listening PHP Remote Debug session shows "Listening for Xdebug on port N" instead of "Running…"; clearing the only field of a debug-only remote type keeps the form and shows the field as required; php-debug leaves the generic Debug adapter list until it has a launch template (#1623).

Co-authored-by: DanielADK <[email protected]>

src/features/debugger/startFailure.ts

@@ -0,0 +1,16 @@
+/**
+ * Why a debug session didn't start, as the user reads it. An adapter that listens for
+ * the debuggee (php-debug waiting for Xdebug) fails with Node's
+ * `listen EADDRINUSE: address already in use :::9003` when another IDE holds the port.
+ */
+import { tx } from "@/platform/i18n";
+
+const PORT_IN_USE = /\bEADDRINUSE\b.*:(\d+)\s*$/;
+
+export function startFailureMessage(e: unknown): string {
+  const message = e instanceof Error ? e.message : String(e);
+  const port = PORT_IN_USE.exec(message)?.[1];
+  return port
+    ? tx`Port ${port} is already in use: another IDE or debug session may be listening on it. Stop it or choose another port.`
+    : message;
+}