fix(gui): embed VST GUI show on mount, health-check timeout/retry, send preset in fx chain (issues 1/3/4)

app/static/js/app.jsx

@@ -11920,6 +11920,10 @@ const ExportModal = ({ open, onClose, exportSettings, setExportSettings, isExpor
           if (!deadRef.current) { deadRef.current = true; setDead(true); onDead && onDead(); }
         });
       }, 2000);
+      // Show immediately on mount even before the rect is known: bridge
+      // re-shows the native window at its last position, and the ~500ms
+      // rect refresh below re-anchors it over the panel.
+      try { fetch(url + '/show', { method: 'POST' }).catch(() => {}); } catch (e) {}
       return () => {
         clearInterval(tick); clearInterval(ping);
         // Panel closed -> hide the native window (bridge stays alive so
@@ -11955,7 +11959,12 @@ const ExportModal = ({ open, onClose, exportSettings, setExportSettings, isExpor
               const rb = boxRef.current.getBoundingClientRect();
               screenRectRef.current = { x: Math.round(pos.x + rb.left * sf), y: Math.round(pos.y + rb.top * sf), w: Math.round(rb.width * sf), h: Math.round(rb.height * sf) };
               maybeShow();
-            }).catch(() => {});
+            }).catch(() => {
+              if (!alive || !boxRef.current) return;
+              const rb = boxRef.current.getBoundingClientRect();
+              screenRectRef.current = { x: Math.round((window.screenX || 0) + rb.left), y: Math.round((window.screenY || 0) + rb.top), w: Math.round(rb.width), h: Math.round(rb.height) };
+              maybeShow();
+            });
           } else {
             screenRectRef.current = { x: Math.round((window.screenX || 0) + r.left), y: Math.round((window.screenY || 0) + r.top), w: Math.round(r.width), h: Math.round(r.height) };
             maybeShow();
@@ -12663,7 +12672,7 @@ const MasteringModal = ({ isOpen, onClose, masteringSettings, setMasteringSettin
   // mix). v1: master chain only — per-track vstChain stays offline (defer).
   React.useEffect(() => {
     if (!window.NativeBridgeService || !window.NativeBridgeService.setFxChain) return;
-    const chain = (ozState.vstFxChain || []).map(s => ({ path: s.path || '', bypass: !!s.bypass }));
+    const chain = (ozState.vstFxChain || []).map(s => ({ path: s.path || '', bypass: !!s.bypass, preset_b64: s.preset_b64 || '' }));
     window.NativeBridgeService.setFxChain(JSON.stringify(chain));
   }, [ozState.vstFxChain]);
   const toggleMasterVst = (idx) => setMasterVstChain(masterVstChain.map((s, i) => i === idx ? { ...s, bypass: !s.bypass } : s));
@@ -21363,9 +21372,20 @@ const App = () => {
     return () => observer.disconnect();
   }, [timelineWrapperNode]);
   useEffect(() => {
-    fetch(API_BASE_URL).then(r => {
-      if (r.ok) setServerStatus('connected'); else setServerStatus('error');
-    }).catch(() => setServerStatus('offline'));
+    let cancelled = false, busy = false, iv = null;
+    const check = () => {
+      if (busy || cancelled) return;
+      busy = true;
+      const ctl = new AbortController();
+      const t = setTimeout(() => ctl.abort(), 3000);
+      fetch(API_BASE_URL, { signal: ctl.signal })
+        .then(r => { if (!cancelled) setServerStatus(r.ok ? 'connected' : 'error'); })
+        .catch(() => { if (!cancelled) setServerStatus('offline'); })
+        .finally(() => { busy = false; clearTimeout(t); });
+    };
+    check();
+    iv = setInterval(() => { if (!cancelled) check(); }, 3000);
+    return () => { cancelled = true; if (iv) clearInterval(iv); };
   }, []);
 
   // ── Computed Values ──
@@ -29413,7 +29433,7 @@ STRICT CONSTRAINTS:
   }), /*#__PURE__*/React.createElement("div", {
     className: "flex items-center gap-2 px-2"
   }, /*#__PURE__*/React.createElement("span", {
-    className: `text-xs font-bold uppercase px-1.5 py-0.5 rounded ${serverStatus === 'connected' ? 'bg-emerald-950 text-emerald-400' : serverStatus === 'checking' ? 'bg-amber-950 text-amber-400' : 'bg-red-950 text-red-400'}`
+    className: `text-xs font-bold uppercase px-1.5 py-0.5 rounded ${serverStatus === 'connected' ? 'bg-emerald-950 text-emerald-400' : serverStatus === 'checking...' ? 'bg-amber-950 text-amber-400' : 'bg-red-950 text-red-400'}`
   }, "Server: ", serverStatus, serverAddr ? " · " + serverAddr : ""), /*#__PURE__*/React.createElement("button", {
     onClick: () => setShowAIConfig(!showAIConfig),
     className: `px-1.5 py-0.5 rounded text-xs border transition ${showAIConfig ? 'bg-purple-900 text-purple-200 border-purple-700' : 'bg-zinc-800 text-zinc-400 border-zinc-700 hover:text-zinc-200'}`