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

pyproject.toml

@@ -0,0 +1,23 @@
+[project]
+name = "stl-repo"
+version = "0.1.0"
+description = "Add your description here"
+readme = "README.md"
+requires-python = ">=3.12"
+dependencies = [
+    "fastapi>=0.136.1",
+    "numpy>=2.4.4",
+    "pillow>=12.2.0",
+    "pydantic>=2.13.3",
+    "python-multipart>=0.0.26",
+    "qrcode[pil]>=8.2",
+    "sqlalchemy>=2.0.49",
+    "trimesh>=4.12.1",
+    "uvicorn>=0.46.0",
+]
+
+[dependency-groups]
+dev = [
+    "httpx>=0.28.1",
+    "pytest>=9.0.3",
+]