⚡ Introduce a new high-performing standalone chat API (#1200)

Closes #1154

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
	- Added authentication functionality for user sessions in chat API.
- Introduced chat-related API endpoints for starting, previewing, and
continuing chat sessions, and streaming messages.
- Implemented WhatsApp API webhook handling for receiving and processing
messages.
- Added environment variable `NEXT_PUBLIC_CHAT_API_URL` for chat API URL
configuration.

- **Bug Fixes**
	- Adjusted file upload logic to correctly determine the API host.
	- Fixed message streaming URL in chat integration with OpenAI.

- **Documentation**
- Updated guides for creating blocks, local installation, self-hosting,
and deployment to use `bun` instead of `pnpm`.

- **Refactor**
	- Refactored chat API functionalities to use modular architecture.
- Simplified client log saving and session update functionalities by
using external functions.
	- Transitioned package management and workflow commands to use `bun`.

- **Chores**
- Switched to `bun` for package management in Dockerfiles and GitHub
workflows.
	- Added new Dockerfile for chat API service setup with Bun framework.
	- Updated `.prettierignore` and documentation with new commands.

- **Style**
	- No visible changes to end-users.

- **Tests**
	- No visible changes to end-users.

- **Revert**
	- No reverts in this release.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/embeds/js/src/utils/guessApiHost.ts

@@ -1,6 +1,29 @@
 import { getRuntimeVariable } from '@typebot.io/env/getRuntimeVariable'
 
-const cloudViewerUrl = 'https://typebot.io'
+const chatApiCloudFallbackHost = 'https://chat.typebot.io'
 
-export const guessApiHost = () =>
-  getRuntimeVariable('NEXT_PUBLIC_VIEWER_URL')?.split(',')[0] ?? cloudViewerUrl
+type Params = {
+  ignoreChatApiUrl?: boolean
+}
+
+export const guessApiHost = (
+  { ignoreChatApiUrl }: Params = { ignoreChatApiUrl: false }
+) => {
+  const chatApiUrl = getRuntimeVariable('NEXT_PUBLIC_CHAT_API_URL')
+  const newChatApiOnUrls = getRuntimeVariable(
+    'NEXT_PUBLIC_USE_EXPERIMENTAL_CHAT_API_ON'
+  )
+
+  if (
+    !ignoreChatApiUrl &&
+    chatApiUrl &&
+    (!newChatApiOnUrls || newChatApiOnUrls.includes(window.location.href))
+  ) {
+    return chatApiUrl
+  }
+
+  return (
+    getRuntimeVariable('NEXT_PUBLIC_VIEWER_URL')?.split(',')[0] ??
+    chatApiCloudFallbackHost
+  )
+}