Add BeanFlows MVP: coffee analytics dashboard, API, and web app

- Fix pipeline granularity: add market_year to cleaned/serving SQL models
- Add DuckDB data access layer with async query functions (analytics.py)
- Build Chart.js dashboard: supply/demand, STU ratio, top producers, YoY table
- Add country comparison page with multi-select picker
- Replace items CRUD with read-only commodity API (list, metrics, countries, CSV)
- Configure BeanFlows plan tiers (Free/Starter/Pro) with feature gating
- Rewrite public pages for coffee market intelligence positioning
- Remove boilerplate items schema, update health check for DuckDB
- Add test suite: 139 tests passing (dashboard, API, billing)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/.gitignore

@@ -0,0 +1,37 @@
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+.venv/
+venv/
+.uv/
+
+# Environment
+.env
+.env.local
+
+# Database
+*.db
+*.db-shm
+*.db-wal
+data/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Testing
+.pytest_cache/
+.coverage
+htmlcov/
+
+# Build
+dist/
+build/
+*.egg-info/