Initial commit: step2urdf tool with handtuned JSON import.

Includes FastAPI backend, vendored step2urdf frontend, and A7 handtuned arm JSON for URDF generation.

app/config.py

@@ -0,0 +1,46 @@
+"""STEP → URDF conversion tool (Web MVP).
+
+Pipeline:
+  STEP upload → assembly/part parse → profile link grouping
+  → Zhipu joint proposal → human review → URDF (+ optional meshes)
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+class Settings(BaseSettings):
+    model_config = SettingsConfigDict(
+        env_file=str(ROOT / ".env"),
+        env_file_encoding="utf-8",
+        extra="ignore",
+    )
+
+    zhipu_api_key: str = ""
+    zhipu_model: str = "glm-4-plus"
+    zhipu_base_url: str = "https://open.bigmodel.cn/api/paas/v4"
+
+    host: str = "127.0.0.1"
+    port: int = 8787
+    data_dir: Path = ROOT / "data"
+
+    default_step: str = ""
+
+    @property
+    def uploads_dir(self) -> Path:
+        return self.data_dir / "uploads"
+
+    @property
+    def jobs_dir(self) -> Path:
+        return self.data_dir / "jobs"
+
+
+settings = Settings()
+settings.uploads_dir.mkdir(parents=True, exist_ok=True)
+settings.jobs_dir.mkdir(parents=True, exist_ok=True)