Increase the length of unsaved doc time before the editor is locked (#23431)

* Use opInflightSince to measure unsaved doc time
* Use performance.now() for lastAcked timestamp
* Use inflightOpCreatedAt
* Increase MAX_UNSAVED_ALERT_SECONDS to 15
* Increase MAX_UNSAVED_SECONDS to 30
* Increase FATAL_OP_TIMEOUT to 45000
* Convert "Connection lost" modal to a notification

GitOrigin-RevId: 2d4233723620fd03ce6d6c5795c48c33c0b2f92c

services/web/frontend/js/features/ide-react/editor/document-container.ts

@@ -182,6 +182,10 @@ export class DocumentContainer extends EventEmitter {
     return this.doc?.getRecentAck()
   }
 
+  getInflightOpCreatedAt() {
+    return this.doc?.getInflightOpCreatedAt()
+  }
+
   hasBufferedOps() {
     return this.doc?.hasBufferedOps()
   }
@@ -354,7 +358,7 @@ export class DocumentContainer extends EventEmitter {
       pendingOpSize < MAX_PENDING_OP_SIZE
     ) {
       // There is an op waiting to go to server but it is small and
-      // within the flushDelay, this is OK for now.
+      // within the recent ack limit, this is OK for now.
       saved = true
       debugConsole.log(
         '[pollSavedStatus] pending op (small with recent ack) assume ok',