feat(wasm): WebAssembly-compiled Cinch engine & interactive playground

[00200200]

Closes #29

Summary of Changes

• Wasm & Pyodide Core Engine (src/cinch/wasm.py):
  • Implements doc_from_markdown, compile_skill, compile_all_dialects, validate_skill, and compile_json.
  • Zero-dependency JSON interop entry point tailored for Pyodide/WebAssembly and browser environments.
  • Sub-10ms compilation performance benchmarked across all 12 AI harness dialects.
• In-Browser Playground (docs/index.html):
  • Live split-screen interface (markdown editor on left, 12 reactive dialect tabs on right).
  • WebAssembly/Pyodide execution with instant fallback engine.
  • Diagnostics warning/error banner, latency performance metrics counter, sample skill selector, and 1-click clipboard copy.
• Test Suite (tests/test_wasm.py):
  • Full unit test coverage for parsing, single-target translation, multi-dialect translation, diagnostics validation, JSON interop, and benchmark verification (<10ms).

[github-actions]

👋 Thanks for opening this pull request, @00200200!

We're thrilled to have your contribution to cinch! Here is a quick checklist to help get your PR merged smoothly:

• Linked Issue: Issue reference detected in PR body. ✅
• Local Verification: Verify all checks pass locally using uv run pytest and uv run ruff check ..
• Commit Hygiene: Ensure commit messages follow conventional commit style (feat:, fix:, docs:).

A maintainer will review your code shortly. Feel free to ping in comments if you have any questions! 🚀

[github-actions]

👋 Thanks for opening this pull request, @00200200!

Here is the automated review checklist for this update:

• Linked Issue: Issue reference detected in PR body. ✅
• Local Verification: Verify all checks pass locally using uv run pytest and uv run ruff check ..
• Commit Hygiene: Ensure commit messages follow conventional commit style (feat:, fix:, docs:).

A maintainer will review your code shortly. Feel free to ping in comments if you have any questions! 🚀