feat: dashboard provider support and session creation improvements (#1092)

Add provider icons and session creation from the dashboard UI.
Sessions can now be created with cloud providers (Browserbase,
Browserless, Browser Use, Kernel) in addition to local engines.

CLI changes:
- Track provider via .provider files alongside .engine files
- Add WaitUntil::None variant to skip lifecycle event waits for providers
- Auto-set waitUntil=none when --provider is used with navigate
- Fix Browser Use: use direct WSS connection (wss://connect.browser-use.com)
- Add connect_cdp_direct for providers with page-level CDP proxies
- Fix resolve_cdp_url to convert https:// provider URLs to wss://
- Treat empty CDP session_id as None (omit from protocol messages)
- Fix Browserbase: send explicit JSON body + Content-Type header
- Increase CDP connect timeout to 25s for remote providers
- Clean up .provider files on session close

Dashboard changes:
- Show provider or engine icon per session in sidebar
- New session dialog with unified engine/provider selector grid
- Async session creation with loading state and error display
- Kill zombie daemons on provider connection failure
- Parse CLI JSON error output for user-friendly messages
- Default new session URL to https://agent-browser.dev

cli/src/native/daemon.rs

@@ -63,6 +63,7 @@ pub async fn run_daemon(session: &str) {
     let stream_path = socket_dir.join(format!("{}.stream", session));
     let _ = fs::remove_file(&stream_path);
     let _ = fs::remove_file(socket_dir.join(format!("{}.engine", session)));
+    let _ = fs::remove_file(socket_dir.join(format!("{}.provider", session)));
     let _ = fs::remove_file(socket_dir.join(format!("{}.extensions", session)));
 
     if let Ok(days_str) = env::var("AGENT_BROWSER_STATE_EXPIRE_DAYS") {
@@ -119,6 +120,7 @@ pub async fn run_daemon(session: &str) {
     let _ = fs::remove_file(&pid_path);
     let _ = fs::remove_file(&stream_path);
     let _ = fs::remove_file(socket_dir.join(format!("{}.engine", session)));
+    let _ = fs::remove_file(socket_dir.join(format!("{}.provider", session)));
     let _ = fs::remove_file(socket_dir.join(format!("{}.extensions", session)));
 
     if let Err(e) = result {