webui: Update status indicators

- Remove green dot connection indicator
- Add DISCONNECTED state with red styling when connection is lost
- Update the status bar to show DISCONNECTED instead of IDLE/WORKING when disconnected
- Create demo page to preview all three status states

Co-Authored-By: sketch <hello@sketch.dev>
Change-ID: skR3m0v3Gr3nD0tD1sc0nn3ct3dR3d

Change-ID: sa2b3679b9cdcaf80k
diff --git a/webui/src/web-components/sketch-app-shell.ts b/webui/src/web-components/sketch-app-shell.ts
index aebabd9..3c39a55 100644
--- a/webui/src/web-components/sketch-app-shell.ts
+++ b/webui/src/web-components/sketch-app-shell.ts
@@ -1022,6 +1022,7 @@
               ? this.messages[this.messages.length - 1]?.end_of_turn &&
                 !this.messages[this.messages.length - 1]?.parent_conversation_id
               : true}
+            .isDisconnected=${this.connectionStatus === "disconnected"}
           ></sketch-call-status>
 
           <sketch-network-status