fix: multiple bug fixes found during comprehensive test plan sweep

- Fix #5: Preset state lost on service restart — call restore_state()
  in PresetManager.__init__() so last active preset is tracked after boot
- Fix #14: Block bypass/toggle WS sync — add WebSocket connection
  in SPA with block_toggled handler that calls loadState()
- Fix #15: IR file naming — add display_name property to IRFile
  dataclass that strips common IR prefixes/suffixes
- Fix: block_id regeneration on every preset load — pass block_id
  from stored JSON data to FXBlock constructor in _preset_from_dict
  (both preset chain and snapshot chain)

src/web/ui-v2-dist/index.html

@@ -945,6 +945,22 @@ async function pollTuner(){
 function startPolling(){stopPolling();loadState();pollTimer=setInterval(loadState,2000);}
 function stopPolling(){if(pollTimer){clearInterval(pollTimer);pollTimer=null;}}
 
+// ═══ WebSocket — real-time updates ═══
+let ws=null;
+function setupWebSocket(){
+  if(ws)try{ws.close()}catch(e){}
+  const proto=location.protocol==='https:'?'wss:':'ws:';
+  ws=new WebSocket(proto+'//'+location.host+'/ws');
+  ws.onmessage=(ev)=>{
+    try{
+      const msg=JSON.parse(ev.data);
+      if(msg.type==='block_toggled'){loadState();}
+    }catch(e){}
+  };
+  ws.onclose=()=>{setTimeout(setupWebSocket,3000);};
+  ws.onerror=()=>{};
+}
+
 // ═══ Init! ═══
 function init(){
   // Restore saved channel
@@ -1243,8 +1259,9 @@ function init(){
   document.getElementById('dlSearchBtn').onclick=doDlSearch;
   document.getElementById('dlSearch').onkeydown=(e)=>{if(e.key==='Enter')doDlSearch();};
 
-  // Start polling
+  // Start polling + WebSocket
   startPolling();
+  setupWebSocket();
   loadPresets();
   loadSnapshots();
 }