feat: add descriptive model naming and inline rename

- Auto-generate model names: {arch}-{labelType}-{epochs}ep-{classNames}-{YYYYMMDD}
- Add PATCH /api/models/{id}/rename endpoint
- Inline rename UI on Models & Training page
- Download filename uses model name instead of v{N}
- DB migration: add name column to model_versions
- Update all docs to reflect new naming convention

backend/api/models.py

@@ -57,8 +57,9 @@ def download_weights(model_id: int):
     version = training.get_version(model_id)
     if version is None or not os.path.isfile(version["weights_path"]):
         raise HTTPException(404, "No weights for that version")
+    name = version.get('name') or f"v{version['version']}"
     return FileResponse(version["weights_path"], media_type="application/octet-stream",
-                        filename=f"v{version['version']}-best.pt")
+                        filename=f"{name}-best.pt")
 
 
 @router.post("/api/models/{model_id}/promote")
@@ -67,3 +68,18 @@ def promote_model(model_id: int) -> dict:
         return training.promote(model_id)
     except training.TrainingError as exc:
         raise HTTPException(400, str(exc))
+
+
+class RenameRequest(BaseModel):
+    name: str
+
+
+@router.patch("/api/models/{model_id}/rename")
+def rename_model(model_id: int, request: RenameRequest) -> dict:
+    try:
+        version = training.rename(model_id, request.name)
+        if version is None:
+            raise HTTPException(404, "No such model version")
+        return version
+    except training.TrainingError as exc:
+        raise HTTPException(400, str(exc))