Changes:
1. Disable automation detection banner in browser launch
   - Added --disable-blink-features=AutomationControlled
   - Removes 'controlled by automation' banner that interferes with autofill

2. Implement keyboard press step type
   - New 'press' step type for keyboard actions
   - Supports single key or array of keys
   - Enables triggering password manager dropdown programmatically

This enables robust password autofill with progressive fallback:
- Layer 1: Browser autofills naturally (banner removed)
- Layer 2: Verify password filled via execute_js
- Layer 3: Trigger password manager with Arrow Down + Enter

🤖 Generated with Claude Code

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