build: drop redundant force-include; add onnxscript to dev deps

Hatchling's  already picks up assets/;
force-include duplicated each asset and emitted a build warning once
real ONNX files landed. onnxscript is a transitive runtime dep of
torch.onnx.export (PyTorch 2.11+) — make it explicit.

pyproject.toml

@@ -22,6 +22,7 @@ dev = [
     "pytest-asyncio>=0.23.0",
     "httpx>=0.27.0",
     "onnx>=1.15.0",
+    "onnxscript>=0.1",
 ]
 
 [build-system]
@@ -31,9 +32,6 @@ build-backend = "hatchling.build"
 [tool.hatch.build.targets.wheel]
 packages = ["src/ai_mouse"]
 
-[tool.hatch.build.targets.wheel.force-include]
-"src/ai_mouse/assets" = "ai_mouse/assets"
-
 [tool.pytest.ini_options]
 asyncio_mode = "auto"
 testpaths = ["tests"]