feat(web): artists page — add-artist modal + filter watched list

The MusicBrainz search+follow moves into a modal opened by an "Add artist"
button; the main view gets a filter that narrows the watched roster (with a
"N of N" count). Follow keeps the modal open (toast per follow) so several can
be added in a row.

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

web/src/app/artists/artists-client.tsx

@@ -1,8 +1,10 @@
 "use client";
 
-import { useEffect, useState } from "react";
+import { useEffect, useMemo, useState } from "react";
 import { PageHead } from "../_ui/page-head";
 import { SectionHeader } from "../_ui/section-header";
+import { Modal } from "../_ui/modal";
+import { toast } from "../_ui/toast";
 
 type Artist = {
   id: string;
@@ -17,9 +19,12 @@ type Hit = { mbid: string; name: string; disambiguation: string };
 
 export function ArtistsClient() {
   const [artists, setArtists] = useState<Artist[]>([]);
+  const [filter, setFilter] = useState("");
+  const [showAdd, setShowAdd] = useState(false);
   const [query, setQuery] = useState("");
   const [hits, setHits] = useState<Hit[]>([]);
   const [searching, setSearching] = useState(false);
+  const [searched, setSearched] = useState(false);
 
   async function refresh() {
     const res = await fetch("/api/artists");
@@ -36,20 +41,30 @@ export function ArtistsClient() {
     try {
       const res = await fetch(`/api/mb/artists?q=${encodeURIComponent(query.trim())}`);
       setHits(res.ok ? (await res.json()).artists : []);
+      setSearched(true);
     } finally {
       setSearching(false);
     }
   }
 
+  function openAdd() {
+    setShowAdd(true);
+  }
+  function closeAdd() {
+    setShowAdd(false);
+    setQuery("");
+    setHits([]);
+    setSearched(false);
+  }
+
   async function follow(hit: Hit) {
     await fetch("/api/artists", {
       method: "POST",
       headers: { "content-type": "application/json" },
       body: JSON.stringify({ mbid: hit.mbid, name: hit.name }),
     });
-    setHits([]);
-    setQuery("");
-    refresh();
+    toast(`Following ${hit.name}`);
+    refresh(); // keep the modal open so several can be added; the hit flips to "Following"
   }
 
   async function toggleAuto(a: Artist) {
@@ -67,60 +82,41 @@ export function ArtistsClient() {
   }
 
   const followedMbids = new Set(artists.map((a) => a.mbid));
+  const shown = useMemo(() => {
+    const n = filter.trim().toLowerCase();
+    return n ? artists.filter((a) => a.name.toLowerCase().includes(n)) : artists;
+  }, [artists, filter]);
 
   return (
     <div>
       <PageHead title="Artists" eyebrow="The roster · follow & watch" />
 
-      <form className="request-form" onSubmit={search}>
+      <div className="request-form">
+        <button type="button" className="btn accent" onClick={openAdd}>
+          Add artist
+        </button>
         <label className="field">
-          <span>Find an artist</span>
+          <span>Filter</span>
           <input
-            aria-label="artist search"
-            placeholder="Search MusicBrainz…"
-            value={query}
-            onChange={(e) => setQuery(e.target.value)}
+            aria-label="filter artists"
+            placeholder="Filter watched…"
+            value={filter}
+            onChange={(e) => setFilter(e.target.value)}
           />
         </label>
-        <button type="submit" className="btn accent">
-          Search
-        </button>
-        {searching ? <span className="rmeta">searching…</span> : null}
-      </form>
+      </div>
 
-      {hits.length > 0 ? (
-        <>
-          <SectionHeader title="Search results" note={`${hits.length} found`} />
-          <ul className="list">
-            {hits.map((h) => (
-              <li key={h.mbid} className="list-row">
-                <div className="main">
-                  <div className="rtitle">
-                    <a href={`/discover/artist/${h.mbid}?name=${encodeURIComponent(h.name)}`}>{h.name}</a>
-                    {h.disambiguation ? <span className="dim"> — {h.disambiguation}</span> : null}
-                  </div>
-                </div>
-                <div className="actions">
-                  {followedMbids.has(h.mbid) ? (
-                    <span className="following">Following</span>
-                  ) : (
-                    <button className="btn sm" onClick={() => follow(h)}>
-                      Follow
-                    </button>
-                  )}
-                </div>
-              </li>
-            ))}
-          </ul>
-        </>
-      ) : null}
-
-      <SectionHeader title="Watching" note={`${artists.length} artists`} />
+      <SectionHeader
+        title="Watching"
+        note={filter ? `${shown.length} of ${artists.length}` : `${artists.length} artists`}
+      />
       {artists.length === 0 ? (
-        <p className="empty">Not following anyone yet. Search above and follow an artist to start watching their releases.</p>
+        <p className="empty">Not following anyone yet. Use “Add artist” to search MusicBrainz and follow someone.</p>
+      ) : shown.length === 0 ? (
+        <p className="empty">No watched artists match “{filter}”.</p>
       ) : (
         <ul className="list">
-          {artists.map((a) => (
+          {shown.map((a) => (
             <li key={a.id} className="list-row">
               <div className="main">
                 <div className="rtitle">
@@ -128,7 +124,8 @@ export function ArtistsClient() {
                 </div>
                 <div className="rmeta">
                   <span className="score">
-                    {a.haveCount} have <span className="dot">·</span> {a.monitoredCount} monitored <span className="dot">·</span> {a.releaseCount} releases
+                    {a.haveCount} have <span className="dot">·</span> {a.monitoredCount} monitored{" "}
+                    <span className="dot">·</span> {a.releaseCount} releases
                   </span>
                 </div>
               </div>
@@ -150,6 +147,54 @@ export function ArtistsClient() {
           ))}
         </ul>
       )}
+
+      {showAdd ? (
+        <Modal open onClose={closeAdd} title="Add artist">
+          <form className="request-form" style={{ margin: "0 0 6px" }} onSubmit={search}>
+            <label className="field">
+              <span>Find an artist</span>
+              {/* eslint-disable-next-line jsx-a11y/no-autofocus */}
+              <input
+                aria-label="artist search"
+                placeholder="Search MusicBrainz…"
+                value={query}
+                onChange={(e) => setQuery(e.target.value)}
+                autoFocus
+              />
+            </label>
+            <button type="submit" className="btn accent">
+              Search
+            </button>
+            {searching ? <span className="rmeta">searching…</span> : null}
+          </form>
+
+          {hits.length > 0 ? (
+            <ul className="list">
+              {hits.map((h) => (
+                <li key={h.mbid} className="list-row">
+                  <div className="main">
+                    <div className="rtitle">
+                      <a href={`/discover/artist/${h.mbid}?name=${encodeURIComponent(h.name)}`}>{h.name}</a>
+                      {h.disambiguation ? <span className="dim"> — {h.disambiguation}</span> : null}
+                    </div>
+                  </div>
+                  <div className="actions">
+                    {followedMbids.has(h.mbid) ? (
+                      <span className="following">Following</span>
+                    ) : (
+                      <button className="btn sm" onClick={() => follow(h)}>
+                        Follow
+                      </button>
+                    )}
+                  </div>
+                </li>
+              ))}
+            </ul>
+          ) : searched && !searching ? (
+            <p className="muted-note">No matches on MusicBrainz.</p>
+          ) : null}
+        </Modal>
+      ) : null}
     </div>
   );
 }