feat: add support for logging in via the web extension (#41)

Reviewed-on: #41

crates/browser-signer-proxy/README.md

@@ -0,0 +1,55 @@
+# browser-signer-proxy
+
+Proxy to use Nostr Browser signer ([NIP-07](https://github.com/nostr-protocol/nips/blob/master/07.md)) in native applications.
+
+This is a re-implementation of [`nostr-browser-signer-proxy`](https://github.com/nostrdevkit/nostr/tree/master/signer/nostr-browser-signer-proxy)
+using the [`smol`](https://github.com/smol-rs/smol) async runtime instead of tokio.
+
+## Description
+
+This crate provides a local HTTP proxy that communicates with a NIP-07 browser extension
+(e.g., Alby, nos2x) running in a browser tab. Native applications can use this proxy to
+request public keys, sign events, and perform NIP-04/NIP-44 encryption/decryption through
+the browser extension.
+
+The HTTP server is implemented with a minimal, dependency-free approach using `smol::net::TcpListener`
+and manual HTTP/1.1 parsing — avoiding heavy HTTP framework dependencies entirely.
+
+## Usage
+
+```rust
+use browser_signer_proxy::prelude::*;
+
+async fn example() -> Result<(), Error> {
+    // Create the proxy with default options (localhost:7400)
+    let proxy = BrowserSignerProxy::new(BrowserSignerProxyOptions::default());
+
+    // Open the proxy URL in a browser
+    webbrowser::open(&proxy.url())?;
+
+    // Start the proxy server
+    proxy.start().await?;
+
+    // Use it as an async Nostr signer
+    let public_key = proxy.get_public_key_async().await?;
+    println!("Connected with public key: {public_key}");
+
+    Ok(())
+}
+```
+
+## Differences from the tokio-based version
+
+| Feature | tokio (original) | smol (this crate) |
+|---|---|---|
+| Async runtime | `tokio` | `smol` |
+| HTTP server | `hyper` | `smol::net::TcpListener` + manual HTTP/1.1 |
+| Mutex | `tokio::sync::Mutex` | `smol::lock::Mutex` |
+| Shutdown signal | `tokio::sync::Notify` | `event_listener::Event` |
+| Request-response channel | `tokio::sync::oneshot` | `smol::channel::bounded(1)` |
+| Timeout | `tokio::time::timeout` | `smol::future::or` + `smol::Timer` |
+| Task spawning | `tokio::spawn` | `smol::spawn` |
+
+## License
+
+This project is distributed under the MIT software license.