feat(web): restyle Settings + read-only library path panel (Phase 3)

Settings onto the Pressing Plant system: credentials with clear set/unset
affordances, a Library section that shows the configured /music path with a
"change MUSIC_DIR in docker-compose + rebuild" note (honest about the mount
being non-remountable from the UI), restyled scan trigger/result, and the
discovery section. All logic and aria-labels preserved. Completes the
frontend redesign (all pages + shell on one system, both themes).

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

web/src/app/settings/settings-form.tsx

@@ -1,6 +1,8 @@
 "use client";
 
 import { useEffect, useState } from "react";
+import { PageHead } from "../_ui/page-head";
+import { SectionHeader } from "../_ui/section-header";
 
 type Loaded = {
   qobuzEmail: string;
@@ -11,6 +13,14 @@ type Loaded = {
   slskdApiKeySet: boolean;
 };
 
+const DISCOVERY_FIELDS: [string, string][] = [
+  ["discover.intervalHours", "Interval (hours)"],
+  ["discover.maxSeeds", "Max seeds per sweep"],
+  ["discover.similarPerSeed", "Similar per seed"],
+  ["discover.albumsPerArtist", "Albums per artist"],
+  ["discover.minScore", "Min score"],
+];
+
 export function SettingsForm() {
   const [qobuzEmail, setQobuzEmail] = useState("");
   const [qobuzPassword, setQobuzPassword] = useState("");
@@ -101,67 +111,131 @@ export function SettingsForm() {
     setTimeout(() => setDiscoverSaved(false), 1500);
   }
 
+  const secretHint = (set: boolean) => (set ? <span className="set"> · set</span> : null);
+
   return (
-    <>
-      <form onSubmit={submit}>
-        <fieldset>
-          <legend>Qobuz — email/password</legend>
-          <label>Qobuz email <input aria-label="qobuz email" value={qobuzEmail} onChange={(e) => setQobuzEmail(e.target.value)} /></label>
-          <label>Qobuz password <input aria-label="qobuz password" type="password" placeholder={pwSet ? "•••• (set)" : ""} value={qobuzPassword} onChange={(e) => setQobuzPassword(e.target.value)} /></label>
-        </fieldset>
-        <fieldset>
-          <legend>Qobuz — auth token (more reliable; overrides email/password)</legend>
-          <label>Qobuz user ID <input aria-label="qobuz user id" value={qobuzUserId} onChange={(e) => setQobuzUserId(e.target.value)} /></label>
-          <label>Qobuz auth token <input aria-label="qobuz auth token" type="password" placeholder={tokenSet ? "•••• (set)" : ""} value={qobuzToken} onChange={(e) => setQobuzToken(e.target.value)} /></label>
-        </fieldset>
-        <fieldset>
-          <legend>Soulseek (slskd)</legend>
-          <label>slskd URL <input aria-label="slskd url" value={slskdUrl} onChange={(e) => setSlskdUrl(e.target.value)} /></label>
-          <label>slskd API key <input aria-label="slskd api key" type="password" placeholder={keySet ? "•••• (set)" : ""} value={slskdApiKey} onChange={(e) => setSlskdApiKey(e.target.value)} /></label>
-        </fieldset>
-        <button type="submit">Save</button>
-        {saved ? <span> Saved.</span> : null}
+    <div>
+      <PageHead title="Settings" eyebrow="Credentials · library · discovery" />
+
+      {/* ── Credentials ─────────────────────────── */}
+      <form className="settings-section" onSubmit={submit}>
+        <SectionHeader title="Credentials" />
+
+        <div className="subhead">Qobuz — email / password</div>
+        <div className="field-grid">
+          <label className="field">
+            <span>Qobuz email</span>
+            <input aria-label="qobuz email" value={qobuzEmail} onChange={(e) => setQobuzEmail(e.target.value)} />
+          </label>
+          <label className="field">
+            <span>Qobuz password{secretHint(pwSet)}</span>
+            <input
+              aria-label="qobuz password"
+              type="password"
+              placeholder={pwSet ? "•••• stored" : ""}
+              value={qobuzPassword}
+              onChange={(e) => setQobuzPassword(e.target.value)}
+            />
+          </label>
+        </div>
+
+        <div className="subhead">Qobuz — auth token (more reliable; overrides email/password)</div>
+        <div className="field-grid">
+          <label className="field">
+            <span>Qobuz user ID</span>
+            <input aria-label="qobuz user id" value={qobuzUserId} onChange={(e) => setQobuzUserId(e.target.value)} />
+          </label>
+          <label className="field">
+            <span>Qobuz auth token{secretHint(tokenSet)}</span>
+            <input
+              aria-label="qobuz auth token"
+              type="password"
+              placeholder={tokenSet ? "•••• stored" : ""}
+              value={qobuzToken}
+              onChange={(e) => setQobuzToken(e.target.value)}
+            />
+          </label>
+        </div>
+
+        <div className="subhead">Soulseek (slskd)</div>
+        <div className="field-grid">
+          <label className="field">
+            <span>slskd URL</span>
+            <input aria-label="slskd url" value={slskdUrl} onChange={(e) => setSlskdUrl(e.target.value)} />
+          </label>
+          <label className="field">
+            <span>slskd API key{secretHint(keySet)}</span>
+            <input
+              aria-label="slskd api key"
+              type="password"
+              placeholder={keySet ? "•••• stored" : ""}
+              value={slskdApiKey}
+              onChange={(e) => setSlskdApiKey(e.target.value)}
+            />
+          </label>
+        </div>
+
+        <div className="save-row">
+          <button type="submit" className="btn accent">
+            Save
+          </button>
+          {saved ? <span className="saved-note">Saved</span> : null}
+        </div>
       </form>
-      <section>
-        <h2>Library</h2>
-        <p>Scan <code>/music</code> and record what's already on disk as owned + monitored.</p>
-        <button type="button" onClick={requestScan} disabled={scanRequested}>
-          {scanRequested ? "Scan requested…" : "Scan library"}
-        </button>
-        {scanResult ? <p aria-label="scan result">Last scan: {scanResult}</p> : null}
+
+      {/* ── Library ─────────────────────────────── */}
+      <section className="settings-section">
+        <SectionHeader title="Library" />
+        <div className="info-panel">
+          <div>
+            <span className="k">Music path</span> &nbsp; <code>/music</code>
+          </div>
+          <div className="muted-note" style={{ fontFamily: "inherit" }}>
+            Mounted read/write into the worker. To point Lyra at a different folder, set{" "}
+            <code>MUSIC_DIR</code> in <code>docker-compose.yml</code> and rebuild — it can’t be remounted from here.
+          </div>
+        </div>
+        <p className="muted-note">Scan the library to record what’s already on disk as owned + monitored.</p>
+        <div className="save-row">
+          <button type="button" className="btn" onClick={requestScan} disabled={scanRequested}>
+            {scanRequested ? "Scanning…" : "Scan library"}
+          </button>
+          {scanResult ? (
+            <span className="saved-note" aria-label="scan result" style={{ color: "var(--graphite)" }}>
+              Last scan: {scanResult}
+            </span>
+          ) : null}
+        </div>
       </section>
-      <form onSubmit={saveDiscovery}>
-        <h2>Discovery</h2>
-        <label>
-          <input
-            type="checkbox"
-            checked={discoverCfg["discover.enabled"] === "true"}
-            onChange={(e) => setCfg("discover.enabled", e.target.checked ? "true" : "false")}
-          />{" "}
-          Enable scheduled discovery sweep
-        </label>
-        {[
-          ["discover.intervalHours", "Interval (hours)"],
-          ["discover.maxSeeds", "Max seeds per sweep"],
-          ["discover.similarPerSeed", "Similar per seed"],
-          ["discover.albumsPerArtist", "Albums per artist"],
-          ["discover.minScore", "Min score"],
-        ].map(([key, label]) => (
-          <p key={key}>
-            <label>
-              {label}:{" "}
-              <input
-                type="number"
-                step="any"
-                value={discoverCfg[key] ?? ""}
-                onChange={(e) => setCfg(key, e.target.value)}
-              />
+
+      {/* ── Discovery ───────────────────────────── */}
+      <form className="settings-section" onSubmit={saveDiscovery}>
+        <SectionHeader title="Discovery" />
+        <div className="save-row" style={{ margin: "14px 0 4px" }}>
+          <label className="toggle">
+            <input
+              type="checkbox"
+              checked={discoverCfg["discover.enabled"] === "true"}
+              onChange={(e) => setCfg("discover.enabled", e.target.checked ? "true" : "false")}
+            />
+            Scheduled discovery sweep
+          </label>
+        </div>
+        <div className="field-grid">
+          {DISCOVERY_FIELDS.map(([key, label]) => (
+            <label key={key} className="field">
+              <span>{label}</span>
+              <input type="number" step="any" value={discoverCfg[key] ?? ""} onChange={(e) => setCfg(key, e.target.value)} />
             </label>
-          </p>
-        ))}
-        <button type="submit">Save discovery settings</button>
-        {discoverSaved && <span> Saved.</span>}
+          ))}
+        </div>
+        <div className="save-row">
+          <button type="submit" className="btn">
+            Save discovery settings
+          </button>
+          {discoverSaved ? <span className="saved-note">Saved</span> : null}
+        </div>
       </form>
-    </>
+    </div>
   );
 }