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/litestream.yml

@@ -0,0 +1,22 @@
+# Litestream configuration for SQLite replication
+# Supports S3, Cloudflare R2, MinIO, etc.
+
+dbs:
+  - path: /app/data/app.db
+    replicas:
+      # Option 1: AWS S3
+      # - url: s3://your-bucket/beanflows/app.db
+      #   access-key-id: ${AWS_ACCESS_KEY_ID}
+      #   secret-access-key: ${AWS_SECRET_ACCESS_KEY}
+      #   region: us-east-1
+      
+      # Option 2: Cloudflare R2
+      # - url: s3://your-bucket/beanflows/app.db
+      #   access-key-id: ${R2_ACCESS_KEY_ID}
+      #   secret-access-key: ${R2_SECRET_ACCESS_KEY}
+      #   endpoint: https://${R2_ACCOUNT_ID}.r2.cloudflarestorage.com
+      
+      # Option 3: Local file backup (for development)
+      - path: /app/data/backups
+        retention: 24h
+        snapshot-interval: 1h