feat: rewrite the nip-4e implementation (#1)

Make NIP-4e a core feature, not an optional feature.

Note:
- The UI is broken and needs to be updated in a separate PR.

Reviewed-on: #1

crates/ui/src/input/blink_cursor.rs

@@ -56,7 +56,7 @@ impl BlinkCursor {
         cx.spawn(async move |this, cx| {
             Timer::after(INTERVAL).await;
             if let Some(this) = this.upgrade() {
-                this.update(cx, |this, cx| this.blink(epoch, cx)).ok();
+                this.update(cx, |this, cx| this.blink(epoch, cx));
             }
         })
         .detach();
@@ -82,8 +82,7 @@ impl BlinkCursor {
                 this.update(cx, |this, cx| {
                     this.paused = false;
                     this.blink(epoch, cx);
-                })
-                .ok();
+                });
             }
         })
         .detach();