Add comprehensive documentation for Browser Use features

- Introduced custom output format instructions with example code.
- Detailed connection methods for launching and connecting to browsers, including local and remote options.
- Provided guidelines for handling sensitive data securely, including best practices and examples.
- Documented supported LangChain chat models with setup instructions and environment variable requirements.
- Added instructions for customizing the system prompt to control agent behavior.

.github/instructions/output-format.instructions.md

@@ -0,0 +1,49 @@
+---
+description: "The default is text. But you can define a structured output format to make post-processing easier."
+applyTo: '**'
+---
+
+## Custom output format
+With [this example](https://github.com/browser-use/browser-use/blob/main/examples/features/custom_output.py) you can define what output format the agent should return to you.
+
+```python
+from pydantic import BaseModel
+# Define the output format as a Pydantic model
+class Post(BaseModel):
+	post_title: str
+	post_url: str
+	num_comments: int
+	hours_since_post: int
+
+
+class Posts(BaseModel):
+	posts: List[Post]
+
+
+controller = Controller(output_model=Posts)
+
+
+async def main():
+	task = 'Go to hackernews show hn and give me the first  5 posts'
+	model = ChatOpenAI(model='gpt-4o')
+	agent = Agent(task=task, llm=model, controller=controller)
+
+	history = await agent.run()
+
+	result = history.final_result()
+	if result:
+		parsed: Posts = Posts.model_validate_json(result)
+
+		for post in parsed.posts:
+			print('\n--------------------------------')
+			print(f'Title:            {post.post_title}')
+			print(f'URL:              {post.post_url}')
+			print(f'Comments:         {post.num_comments}')
+			print(f'Hours since post: {post.hours_since_post}')
+	else:
+		print('No result')
+
+
+if __name__ == '__main__':
+	asyncio.run(main())
+```