feat: add post3 s3 proxy for postgresql

Signed-off-by: kjuulh <contact@kjuulh.io>

crates/post3-sdk/examples/basic.rs

@@ -0,0 +1,76 @@
+//! Basic post3 usage: create a bucket, put/get/delete objects, list objects.
+//!
+//! Prerequisites: post3-server running on localhost:9000
+//!   mise run up && mise run dev
+//!
+//! Run:
+//!   cargo run -p post3-sdk --example basic
+
+use post3_sdk::Post3Client;
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    let endpoint = std::env::var("POST3_ENDPOINT")
+        .unwrap_or_else(|_| "http://localhost:9000".to_string());
+    let client = Post3Client::new(&endpoint);
+
+    // Create a bucket
+    println!("Creating bucket 'example-bucket'...");
+    client.create_bucket("example-bucket").await?;
+
+    // List buckets
+    let buckets = client.list_buckets().await?;
+    println!("Buckets: {:?}", buckets);
+
+    // Put an object
+    println!("Putting 'hello.txt'...");
+    client
+        .put_object("example-bucket", "hello.txt", b"Hello, post3!")
+        .await?;
+
+    // Get the object back
+    let data = client.get_object("example-bucket", "hello.txt").await?;
+    println!("Got: {}", String::from_utf8_lossy(&data));
+
+    // Put a few more objects
+    client
+        .put_object("example-bucket", "docs/readme.md", b"# README")
+        .await?;
+    client
+        .put_object("example-bucket", "docs/guide.md", b"# Guide")
+        .await?;
+
+    // List all objects
+    let objects = client.list_objects("example-bucket", None).await?;
+    println!("All objects:");
+    for obj in &objects {
+        println!("  {} ({} bytes)", obj.key, obj.size);
+    }
+
+    // List with prefix filter
+    let docs = client
+        .list_objects("example-bucket", Some("docs/"))
+        .await?;
+    println!("Objects under docs/:");
+    for obj in &docs {
+        println!("  {} ({} bytes)", obj.key, obj.size);
+    }
+
+    // Delete objects
+    println!("Cleaning up...");
+    client
+        .delete_object("example-bucket", "hello.txt")
+        .await?;
+    client
+        .delete_object("example-bucket", "docs/readme.md")
+        .await?;
+    client
+        .delete_object("example-bucket", "docs/guide.md")
+        .await?;
+
+    // Delete the bucket
+    client.delete_bucket("example-bucket").await?;
+    println!("Done!");
+
+    Ok(())
+}