fix: address Playwright API audit findings

- Replace deprecated Locator.Type() with PressSequentially() (node.go)
- Close page on Goto failure to prevent resource leak (playwright.go)
- Fix teardown order: close context before browser (playwright.go)
- Clean up resources on NewPage failure (interactive.go)
- Spawn cleanup goroutine on context cancellation in both constructors

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

node.go

@@ -29,7 +29,7 @@ type node struct {
 }
 
 func (n node) Type(input string) error {
-	return n.locator.Type(input)
+	return n.locator.PressSequentially(input)
 }
 
 func (n node) Click() error {