Add option to use existing llama.cpp build

README.md

@@ -38,10 +38,12 @@ run-pipeline.sh            → Run finetune → merge/convert → run in sequenc
 
 `setup.sh` will:
 1. Create a Python virtual environment and install Python dependencies
-2. Clone [llama.cpp](https://github.com/ggml-org/llama.cpp)
-3. Build llama.cpp with your selected GPU backend
+2. Clone [llama.cpp](https://github.com/ggml-org/llama.cpp) or symlink an existing build
+3. Build llama.cpp with your selected GPU backend (skip if using existing)
 4. Install llama-cpp-python bindings with matching backend flags
 
+**Using an existing llama.cpp build:** Choose option 2 and provide the absolute path to your existing build. Setup will create a symlink at `./llama.cpp`.
+
 ### Backend Selection
 
 | Choice | Backend | Requirements |