Add comprehensive framework architecture and Playwright implementation docs

- ARCHITECTURE.md: Complete framework documentation covering directory
  structure, execution flow, action system, element location, parameter
  system, shared variables, utilities, and module details

- PLAYWRIGHT_IMPLEMENTATION.md: Detailed Playwright implementation guide
  with design decisions, parameter mappings, code templates, and
  implementation checklist

https://claude.ai/code/session_01VibqKxxfPc8Npuk5tXfvCf

Author: claude