add DEPLOY.md

DEPLOY.md

@@ -1,5 +1,7 @@
 # Deploying BgFilter to a Linux server
 
+> 中文版：[DEPLOY_ZH.md](DEPLOY_ZH.md)
+
 This guide covers everything needed to run the BgFilter HTTP service
 (`POST /remove-background`, `GET /healthz`) on a Linux server. It assumes a CPU
 deployment (the default); GPU notes are called out where relevant.
@@ -99,7 +101,38 @@ the `hub/` folder over.
 ### Option B — plain folders inside the project
 
 Drop each model into `models/<repo-basename>/` and the loader uses it directly (no
-HF cache, no network). Absent folders fall back to the repo id, so this is opt-in:
+HF cache, no network). Absent folders fall back to the repo id, so this is opt-in.
+
+**The folder name must match the repo basename exactly** — that is how the loader
+finds it (`ZhengPeng7/BiRefNet` → `models/BiRefNet`). Required files per model:
+
+```text
+<project-root>/
+└── models/
+    ├── vitmatte-base-composition-1k/     # ViTMatte matting model
+    │   ├── config.json
+    │   ├── preprocessor_config.json
+    │   └── pytorch_model.bin             # ~369 MB
+    ├── BiRefNet/                         # default segmenter (trust_remote_code)
+    │   ├── config.json
+    │   ├── BiRefNet_config.py            # custom code — required by trust_remote_code
+    │   ├── birefnet.py                   # custom code — required by trust_remote_code
+    │   └── model.safetensors             # ~424 MB
+    └── anime-seg/                        # optional segmenter (seg_model=anime-seg)
+        └── isnetis.onnx                  # ~168 MB
+```
+
+Notes:
+- **ViTMatte**: needs `config.json`, `preprocessor_config.json`, and the weights
+  (`pytorch_model.bin`; `model.safetensors` also works if present).
+- **BiRefNet**: the two `.py` files are mandatory — `trust_remote_code` executes them
+  to build the model. Keep `config.json` + `model.safetensors` alongside them. (The
+  repo's `handler.py` / `requirements.txt` / `README.md` are not needed.)
+- **anime-seg**: only `isnetis.onnx` is read; nothing else is required.
+- `anime-seg` is optional — omit its folder if you never use `seg_model=anime-seg`.
+
+The easiest way to populate the folders is to let `hf download` fetch them (it also
+pulls a couple of unused files like `README.md`, which is harmless):
 
 ```bash
 hf download hustvl/vitmatte-base-composition-1k --local-dir models/vitmatte-base-composition-1k