chore: reorganize into polyglot monorepo (workshop)

- Move bigmind/ -> mcp/bigmind/
- Move webscraper/ -> mcp/webscraper/
- Move mss-failsafe/ -> java/mss-failsafe/
- Move Wellmann-Shop/ -> java/wellmann-shop/ (normalize to kebab-case)
- Add .roo/ IDE config files to tracking
- Add plans/REPO_STRATEGY.md (monorepo strategy document)
- Expand .gitignore: Java/Maven, Node/TS, coverage, uv.lock
- Rewrite README.md as navigation index
- Update .roo/mcp.json webscraper path to mcp/webscraper/

mcp/bigmind/.gitignore

@@ -0,0 +1,5 @@
+*.html
+__pycache__/
+.venv/
+*.pyc
+.pytest_cache/