docs: add GitHub links to example files in sacp and sacp-proxy

Added clickable links to example files in the crate-level documentation:

sacp:
- simple_agent.rs - Minimal agent implementation
- yolo_one_shot_client.rs - Complete client example

sacp-proxy:
- minimal.rs - Simplest possible proxy
- with_mcp_server.rs - Proxy that adds MCP tools

This makes it easier for users reading the docs to navigate directly
to the example code on GitHub.

Author: nikomatsakis

src/sacp-proxy/src/lib.rs

@@ -85,8 +85,10 @@
 //!
 //! ## Examples
 //!
-//! - **`minimal.rs`** - Simplest possible proxy that forwards everything unchanged
-//! - **`with_mcp_server.rs`** - Proxy that adds MCP tools to any agent
+//! See the [examples directory](https://github.com/symposium-org/symposium-acp/tree/main/src/sacp-proxy/examples):
+//!
+//! - **[`minimal.rs`](https://github.com/symposium-org/symposium-acp/blob/main/src/sacp-proxy/examples/minimal.rs)** - Simplest possible proxy that forwards everything unchanged
+//! - **[`with_mcp_server.rs`](https://github.com/symposium-org/symposium-acp/blob/main/src/sacp-proxy/examples/with_mcp_server.rs)** - Proxy that adds MCP tools to any agent
 //!
 //! ## How Proxies Work
 //!

src/sacp/src/lib.rs

@@ -49,8 +49,8 @@
 //!
 //! You may also enjoy looking at some of these examples:
 //!
-//! - **`simple_agent.rs`** - Minimal agent implementation
-//! - **`yolo_one_shot_client.rs`** - Complete client that spawns an agent and sends a prompt
+//! - **[`simple_agent.rs`](https://github.com/symposium-org/symposium-acp/blob/main/src/sacp/examples/simple_agent.rs)** - Minimal agent implementation
+//! - **[`yolo_one_shot_client.rs`](https://github.com/symposium-org/symposium-acp/blob/main/src/sacp/examples/yolo_one_shot_client.rs)** - Complete client that spawns an agent and sends a prompt
 //! - **[`elizacp`](https://crates.io/crates/elizacp)** - Full working agent with session management (also useful for testing)
 //! - **[`sacp-conductor`](https://crates.io/crates/sacp-conductor)** - The "conductor" is an ACP agent that composes proxy components with a final agent.
 //!