Add gsio-client and gsio-wallet crates with initial implementations

- Introduced `gsio-client` crate for interacting with GSIO nodes, including ledger entry management and node discovery.
- Introduced `gsio-wallet` crate for key management, transaction creation, and wallet functionality.
- Updated workspace configuration to include new crates.

crates/gsio-client/examples/basic_usage.rs

@@ -0,0 +1,41 @@
+use gsio_client::{GsioClient, GsioClientError};
+use serde_json::json;
+use tracing_subscriber::FmtSubscriber;
+
+#[tokio::main]
+async fn main() -> Result<(), GsioClientError> {
+    // Initialize tracing
+    tracing::subscriber::set_global_default(FmtSubscriber::default())
+        .expect("Failed to set tracing subscriber");
+
+    // Create a new client
+    let client = GsioClient::new("http://localhost:3000")?;
+    println!("Created GSIO client");
+
+    // Add an entry to the ledger
+    let entry_data = json!({
+        "message": "Hello, GSIO!",
+        "timestamp": chrono::Utc::now().to_rfc3339(),
+    });
+
+    let entry = client.add_ledger_entry(entry_data).await?;
+    println!("Added ledger entry: {:?}", entry);
+
+    // Get all entries in the ledger
+    let entries = client.get_ledger().await?;
+    println!("Ledger entries:");
+    for entry in entries {
+        println!("  - {}: {}", entry.id, entry.data);
+    }
+
+    // Get all known nodes
+    let nodes = client.get_known_nodes().await?;
+    println!("Known nodes:");
+    for node in nodes {
+        println!("  - {}", node);
+    }
+
+    println!("Example completed successfully");
+
+    Ok(())
+}