native (#594)

* Native Rust rewrite of agent-browser daemon

Single-binary Rust implementation replacing the Node.js/Playwright daemon
with direct CDP (Chrome DevTools Protocol) communication. Includes full
command parity, WebDriver/Safari/iOS backend routing, request tracking,
frame context management, CDP protocol codegen, and comprehensive tests.

* improvements

* fix ci

* fixes

* faster builds

cli/src/native/webdriver/backend.rs

@@ -0,0 +1,142 @@
+use async_trait::async_trait;
+use serde_json::Value;
+
+/// Abstract backend for browser automation. CDP (Chromium) and WebDriver
+/// (Safari/iOS) share this interface so actions.rs can remain backend-agnostic
+/// in the future.
+#[async_trait]
+pub trait BrowserBackend: Send + Sync {
+    async fn navigate(&self, url: &str) -> Result<(), String>;
+    async fn get_url(&self) -> Result<String, String>;
+    async fn get_title(&self) -> Result<String, String>;
+    async fn get_content(&self) -> Result<String, String>;
+    async fn evaluate(&self, script: &str) -> Result<Value, String>;
+    async fn screenshot(&self) -> Result<String, String>;
+    async fn click(&self, selector: &str) -> Result<(), String>;
+    async fn fill(&self, selector: &str, value: &str) -> Result<(), String>;
+    async fn close(&mut self) -> Result<(), String>;
+    async fn back(&self) -> Result<(), String>;
+    async fn forward(&self) -> Result<(), String>;
+    async fn reload(&self) -> Result<(), String>;
+    async fn get_cookies(&self) -> Result<Value, String>;
+    fn backend_type(&self) -> &str;
+
+    fn supports(&self, feature: &str) -> bool {
+        match feature {
+            "navigate" | "evaluate" | "screenshot" | "click" | "fill" => true,
+            "screencast" | "tracing" | "network_intercept" | "cdp" => self.backend_type() == "cdp",
+            _ => false,
+        }
+    }
+
+    fn unsupported_error(&self, action: &str) -> String {
+        format!(
+            "Action '{}' is not supported on the {} backend",
+            action,
+            self.backend_type()
+        )
+    }
+}
+
+/// WebDriver implementation of BrowserBackend
+pub struct WebDriverBackend {
+    client: super::client::WebDriverClient,
+}
+
+impl WebDriverBackend {
+    pub fn new(client: super::client::WebDriverClient) -> Self {
+        Self { client }
+    }
+}
+
+#[async_trait]
+impl BrowserBackend for WebDriverBackend {
+    async fn navigate(&self, url: &str) -> Result<(), String> {
+        self.client.navigate(url).await
+    }
+
+    async fn get_url(&self) -> Result<String, String> {
+        self.client.get_url().await
+    }
+
+    async fn get_title(&self) -> Result<String, String> {
+        self.client.get_title().await
+    }
+
+    async fn get_content(&self) -> Result<String, String> {
+        self.client.get_page_source().await
+    }
+
+    async fn evaluate(&self, script: &str) -> Result<Value, String> {
+        self.client.execute_script(script, vec![]).await
+    }
+
+    async fn screenshot(&self) -> Result<String, String> {
+        self.client.screenshot().await
+    }
+
+    async fn click(&self, selector: &str) -> Result<(), String> {
+        let element_id = self.client.find_element("css selector", selector).await?;
+        self.client.click_element(&element_id).await
+    }
+
+    async fn fill(&self, selector: &str, value: &str) -> Result<(), String> {
+        let element_id = self.client.find_element("css selector", selector).await?;
+        self.client.clear_element(&element_id).await?;
+        self.client.send_keys(&element_id, value).await
+    }
+
+    async fn close(&mut self) -> Result<(), String> {
+        self.client.delete_session().await
+    }
+
+    async fn back(&self) -> Result<(), String> {
+        self.client.back().await
+    }
+
+    async fn forward(&self) -> Result<(), String> {
+        self.client.forward().await
+    }
+
+    async fn reload(&self) -> Result<(), String> {
+        self.client.refresh().await
+    }
+
+    async fn get_cookies(&self) -> Result<Value, String> {
+        self.client.get_cookies().await
+    }
+
+    fn backend_type(&self) -> &str {
+        "webdriver"
+    }
+}
+
+/// CDP-backed backend constants for unsupported actions on WebDriver
+pub const WEBDRIVER_UNSUPPORTED_ACTIONS: &[&str] = &[
+    "screencast_start",
+    "screencast_stop",
+    "trace_start",
+    "trace_stop",
+    "profiler_start",
+    "profiler_stop",
+    "route",
+    "unroute",
+    "expose",
+    "addscript",
+    "addinitscript",
+    "network",
+    "har_start",
+    "har_stop",
+];
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_unsupported_actions() {
+        assert!(WEBDRIVER_UNSUPPORTED_ACTIONS.contains(&"screencast_start"));
+        assert!(WEBDRIVER_UNSUPPORTED_ACTIONS.contains(&"trace_start"));
+        assert!(!WEBDRIVER_UNSUPPORTED_ACTIONS.contains(&"navigate"));
+    }
+}