webui: Improve dx

For local development, switch to Vite and update web components for improved demo experience. Note that we haven't changed how we bundle when we're actually running in sketch; that's still the go/esbuild in-memory setup. This just changes demo dev setup to get breakpoints working and a functioning full sketch-app-shell.

We still need to add some mock data, but this is a start

- Introduced `vite.config.mts` for Vite setup with hot module reloading.
- Updated `package.json` and `package-lock.json` to include Vite and related plugins.
- Refactored demo scripts to utilize Vite for local development.
- Created `launch.json` for VSCode debugging configuration.
- Enhanced `Makefile` with a new demo task.
- Improved styling and structure in demo HTML and CSS files.
- Implemented `aggregateAgentMessages` function for message handling in web components.
diff --git a/loop/webui/src/web-components/sketch-chat-input.ts b/loop/webui/src/web-components/sketch-chat-input.ts
index c181724..d5ec75e 100644
--- a/loop/webui/src/web-components/sketch-chat-input.ts
+++ b/loop/webui/src/web-components/sketch-chat-input.ts
@@ -79,7 +79,7 @@
 
       // Update the textarea value directly, otherwise it won't update until next render
       const textarea = this.shadowRoot?.querySelector(
-        "#chatInput",
+        "#chatInput"
       ) as HTMLTextAreaElement;
       if (textarea) {
         textarea.value = content;
@@ -96,7 +96,7 @@
     // Listen for update-content events
     this.addEventListener(
       "update-content",
-      this._handleUpdateContent as EventListener,
+      this._handleUpdateContent as EventListener
     );
   }
 
@@ -107,7 +107,7 @@
     // Remove event listeners
     this.removeEventListener(
       "update-content",
-      this._handleUpdateContent as EventListener,
+      this._handleUpdateContent as EventListener
     );
   }