docs: streamable server sample (#595)

- add a simple streamable http server example with auth
- update readme: replace quickstart example from sse server to
streamable server
- add readme files for samples, simple-streamable-server, notebooks

closes #170 

## How Has This Been Tested?
knit and inspector

## Breaking Changes
NaN

## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [x] Documentation update

## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [x] I have added or updated documentation as needed

samples/simple-streamable-server/README.md

@@ -0,0 +1,75 @@
+# Simple Streamable HTTP Server
+
+A minimal MCP server using the recommended Streamable HTTP transport with optional Bearer token authentication.
+
+## Overview
+
+This sample demonstrates a Streamable HTTP MCP server built with Ktor. It exposes tools, a prompt
+template, and a resource over HTTP, and optionally supports Bearer token authentication. The
+`multi-greet` tool showcases server-to-client logging notifications with streaming delays.
+
+## Prerequisites
+
+- JDK 17+
+
+## Build & Run
+
+### Without authentication
+
+```shell
+./gradlew run
+```
+
+The server starts on `http://localhost:3001/mcp` by default.
+
+Connect with the [MCP Inspector](https://modelcontextprotocol.io/docs/tools/inspector):
+
+```shell
+npx @modelcontextprotocol/inspector
+```
+
+In the Inspector UI, select **Streamable HTTP** transport and enter `http://localhost:3001/mcp`.
+
+Pass a port number as an argument to change it:
+
+```shell
+./gradlew run --args="8080"
+```
+
+### With authentication
+
+```shell
+MCP_AUTH_TOKEN=my-secret ./gradlew run --args="--auth"
+```
+
+When `--auth` is passed, clients must include an `Authorization: Bearer <token>` header.
+The token is read from the `MCP_AUTH_TOKEN` environment variable (required when `--auth` is used).
+
+### Authentication caveats
+
+This sample is intended **for demonstration only**. In production you should:
+
+- Use a proper identity provider instead of a static token.
+- Restrict CORS origins to your deployment domain — the sample allows all origins.
+- Serve the endpoint over HTTPS.
+
+## MCP Capabilities
+
+### Tools
+
+| Name | Description |
+|------|-------------|
+| `greet` | Returns a greeting for a given `name`. |
+| `multi-greet` | Sends logging notifications between delayed greetings, demonstrating streaming. |
+
+### Prompts
+
+| Name | Description |
+|------|-------------|
+| `greeting-template` | Generates a friendly greeting message for a given `name`. |
+
+### Resources
+
+| Name | URI | Description |
+|------|-----|-------------|
+| `Default Greeting` | `https://example.com/greetings/default` | Returns a static "Hello, world!" text. |