⚡ 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/schemas/features/chat/schema.ts

@@ -225,14 +225,15 @@ export const startPreviewChatInputSchema = z.object({
     .describe(
       "[Where to find my bot's ID?](../how-to#how-to-find-my-typebotid)"
     ),
-  isStreamEnabled: z.boolean().optional(),
+  isStreamEnabled: z.boolean().optional().default(false),
   message: z.string().optional(),
   isOnlyRegistering: z
     .boolean()
     .optional()
     .describe(
       'If set to `true`, it will only register the session and not start the bot. This is used for 3rd party chat platforms as it can require a session to be registered before sending the first message.'
-    ),
+    )
+    .default(false),
   typebot: startTypebotSchema
     .optional()
     .describe(

packages/schemas/features/whatsapp.ts

@@ -174,6 +174,10 @@ export const whatsAppWebhookRequestBodySchema = z.object({
   ),
 })
 
+export type WhatsAppWebhookRequestBody = z.infer<
+  typeof whatsAppWebhookRequestBodySchema
+>
+
 export const whatsAppCredentialsSchema = z
   .object({
     type: z.literal('whatsApp'),