fix(web): keep focus in modals while typing (add-artist bug)

The Modal focus-trap effect depended on [open, onClose] and called
panelRef.focus() on every run. Callers that pass a fresh onClose each render
(the common case, e.g. artists-client's closeAdd) re-ran the effect on every
parent re-render — so typing one char into the add-artist search (setQuery →
re-render → new onClose) yanked focus off the <input> back onto the panel,
making the field untypable.

Hold the latest onClose in a ref and depend on [open] alone, so focus-on-open
runs once per open. Fixes every Modal caller, not just add-artist.

Verified live via Playwright: typing "radiohead" one key at a time keeps the
value and document.activeElement on the search input.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/src/app/_ui/modal.tsx

@@ -22,6 +22,12 @@ export function Modal({
 }) {
   const panelRef = useRef<HTMLDivElement>(null);
   const lastFocus = useRef<HTMLElement | null>(null);
+  // Keep the latest onClose in a ref so the setup effect can depend on [open] alone. If it
+  // depended on onClose, a caller passing a fresh callback each render (the common case)
+  // would re-run the effect on every parent re-render — and panelRef.focus() below would
+  // yank focus off a just-typed <input> back onto the panel (the add-artist modal bug).
+  const onCloseRef = useRef(onClose);
+  onCloseRef.current = onClose;
 
   useEffect(() => {
     if (!open) return;
@@ -32,7 +38,7 @@ export function Modal({
 
     function onKey(e: KeyboardEvent) {
       if (e.key === "Escape") {
-        onClose();
+        onCloseRef.current();
         return;
       }
       if (e.key !== "Tab") return;
@@ -54,7 +60,7 @@ export function Modal({
       document.body.style.overflow = prevOverflow;
       lastFocus.current?.focus();
     };
-  }, [open, onClose]);
+  }, [open]);
 
   if (!open || typeof document === "undefined") return null;