feat: add SetDefaultTimeout to InteractiveBrowser interface

Adds SetDefaultTimeout(time.Duration) to the InteractiveBrowser interface,
delegating to Playwright's Page and BrowserContext SetDefaultTimeout and
SetDefaultNavigationTimeout methods. This allows callers to set a timeout
so Playwright operations return an error instead of blocking forever when
the browser process crashes or the remote server becomes unresponsive.

Closes #86

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

interactive.go

@@ -48,6 +48,16 @@ type InteractiveBrowser interface {
 	// Cookies returns all cookies from the browser context.
 	Cookies() ([]Cookie, error)
 
+	// SetDefaultTimeout sets the default timeout for all Playwright operations
+	// (navigation, clicks, screenshots, cookie extraction, etc.). A value of 0
+	// disables timeouts. By default, Playwright uses a 30-second timeout.
+	//
+	// This is the primary mechanism for preventing hung sessions: callers can
+	// set a timeout so that any Playwright call returns an error instead of
+	// blocking forever if the browser process crashes or the remote server
+	// becomes unresponsive.
+	SetDefaultTimeout(timeout time.Duration)
+
 	// Close tears down the browser.
 	Close() error
 }
@@ -246,6 +256,14 @@ func (ib *interactiveBrowser) Cookies() ([]Cookie, error) {
 	return cookies, nil
 }
 
+func (ib *interactiveBrowser) SetDefaultTimeout(timeout time.Duration) {
+	ms := float64(timeout.Milliseconds())
+	ib.page.SetDefaultTimeout(ms)
+	ib.page.SetDefaultNavigationTimeout(ms)
+	ib.ctx.SetDefaultTimeout(ms)
+	ib.ctx.SetDefaultNavigationTimeout(ms)
+}
+
 func (ib *interactiveBrowser) Close() error {
 	if ib.detached {
 		return nil