Initial SEO-INTEL documentation: architecture, scoring, code structure

Add comprehensive documentation for the dual-engine performance evaluation system:
- System architecture and data flow
- Score calculation methodology (0-100 approximation from CWV thresholds)
- Detailed metrics reference (LCP, FCP, CLS, TBT, TTFB)
- Testing engines comparison (Sitespeed vs PSI)
- Complete code structure map (file-by-file breakdown)
- Case study: rds.ink 77 score with actionable fixes
- Quick reference guides for interpreting results

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,12 @@
+__pycache__/
+*.py[cod]
+*.pyc
+.DS_Store
+.env
+.venv
+venv/
+*.swp
+*.swo
+*~
+.idea/
+.vscode/