docs: add content to README (install, running samples etc)

Author: ksachdeva

README.md

@@ -1 +1,108 @@
-# Google ADK chatkit
+# OpenAI chatkit support for Google ADK
+
+## Install
+
+```bash
+uv add adk-chatkit
+```
+
+## Running examples
+
+Make sure you open this repository in vscode `devcontainer` and all dependencies will be setup for you
+
+```bash
+# At the root of the repository
+# fill in your configuration / settings
+cp .env.example .env
+```
+
+There is one backend and one frontend that hosts 3 agents (chatkit servers) and their corresponding user interface.
+
+```bash
+# Run the backend
+uv run poe run-example-backend
+```
+
+```bash
+# Run the frontend
+uv run poe run-example-frontend
+```
+
+## Usage
+
+See `examples` for full usage
+
+```python
+
+from adk_chatkit import ADKContext, ADKStore, stream_agent_response
+
+class FactsChatkitServer(ChatKitServer[ADKContext]):
+    def __init__(
+        self,
+        store: ADKStore,
+        runner_manager: RunnerManager,
+        settings: Settings,
+    ) -> None:
+        super().__init__(store)
+        agent = _make_facts_agent(settings)
+        self._runner = runner_manager.add_runner(settings.FACTS_APP_NAME, agent)
+
+    async def respond(
+        self,
+        thread: ThreadMetadata,
+        item: UserMessageItem | None,
+        context: ADKContext,
+    ) -> AsyncIterator[ThreadStreamEvent]:
+        if item is None:
+            return
+
+        if _is_tool_completion_item(item):
+            return
+
+        message_text = _user_message_text(item)
+        if not message_text:
+            return
+
+        content = genai_types.Content(
+            role="user",
+            parts=[genai_types.Part.from_text(text=message_text)],
+        )
+
+        event_stream = self._runner.run_async(
+            user_id=context["user_id"],
+            session_id=thread.id,
+            new_message=content,
+            run_config=RunConfig(streaming_mode=StreamingMode.SSE),
+        )
+
+        async for event in stream_agent_response(thread, event_stream):
+            yield event
+
+```
+
+## Examples applications
+
+There are 3 applications (ported from https://github.com/openai/openai-chatkit-advanced-samples)
+
+### Facts & Guide
+
+- Shows Fact Recording
+- Displays Weather using Widget
+- Theme Switching
+
+http://localhost:5173/guide
+
+### Customer Support
+
+- Airline Reservation Management
+- Change Seat
+- Add bags
+
+http://localhost:5171/customer-support
+
+### Knowledge Assistant
+
+- Answers questions based on files and vector store
+- Shows files and citations
+
+http://localhost:5171/knowledge