Update instruction: running clang-tidy

shared/stinkytofu/README.md

@@ -100,6 +100,36 @@ cmake --build build --target stinkytofu_python
 cmake --build <build_dir> --target stinkytofu_python
 ```
 
+## Run clang-tidy
+
+We use `clang-tidy-20`, so additional installation may required.
+
+### 1. Download and Run the LLVM Setup Script
+This script automatically detects your OS distribution, adds the correct LLVM stable/nightly APT repository, and updates your package lists[span_2](start_span)[span_2](end_span).
+
+```bash
+# Get the official script and make it executable
+wget [https://apt.llvm.org/llvm.sh](https://apt.llvm.org/llvm.sh)
+chmod +x llvm.sh
+
+# Run the script to add repositories
+sudo ./llvm.sh 20 reponly
+```
+
+### Install `clang-tidy-20`
+
+```bash
+sudo apt-get update
+sudo apt-get install -y clang-tidy-20
+```
+
+### Run clang-tidy
+
+```bash
+invoke build
+invoke tidy
+```
+
 ## Test
 
 ```bash