fix: WebDriver v9 frame switching + newline handling

Use switchFrame() instead of removed switchToFrame/switchToParentFrame.
Split typed text on \n and emit Enter keypress (\uE007) between
segments so multi-paragraph content reaches Trix and other
keystroke-driven editors.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: DavertMik

lib/element/WebElement.js

@@ -306,8 +306,15 @@ class WebElement {
       case 'playwright':
       case 'puppeteer':
         return this.helper.page.keyboard.type(s, options)
-      case 'webdriver':
-        return this.helper.browser.keys(s)
+      case 'webdriver': {
+        const ENTER = '\uE007'
+        const parts = s.split('\n')
+        for (let i = 0; i < parts.length; i++) {
+          if (parts[i]) await this.helper.browser.keys(parts[i])
+          if (i < parts.length - 1) await this.helper.browser.keys(ENTER)
+        }
+        return
+      }
       default:
         throw new Error(`Unsupported helper type: ${this.helperType}`)
     }
@@ -364,12 +371,12 @@ class WebElement {
       }
       case 'webdriver': {
         const browser = this.helper.browser
-        await browser.switchToFrame(this.element)
+        await browser.switchFrame(this.element)
         try {
           const body = await browser.$('body')
           return await fn(new WebElement(body, this.helper))
         } finally {
-          await browser.switchToParentFrame()
+          await browser.switchFrame(null)
         }
       }
       default: