feat: implementar 12 mejoras, tests, docs y optimizaciones

- Fase A: license templates, search history, cost estimator
- Fase B: import URL, bulk ZIP, batch download
- Fase C: comparison mode, mesh validation, measurement tool
- Fase D: cross-section clipping, overhang heatmap, layer animation
- Refactor Pydantic/SQLAlchemy warnings
- 24 tests pytest
- README actualizado
- WebP thumbnails, lazy loading, cache headers

docker-compose.yml

@@ -0,0 +1,17 @@
+version: "3.8"
+
+services:
+  stl-repo:
+    build: .
+    container_name: stl-repository
+    ports:
+      - "8000:8000"
+    volumes:
+      - ./data:/app/data
+      - ./uploads:/app/uploads
+      - ./thumbnails:/app/thumbnails
+      - ./images:/app/images
+    environment:
+      - UVICORN_HOST=0.0.0.0
+      - UVICORN_PORT=8000
+    restart: unless-stopped