ci : add older, min and dry-run options to ccache-clear (#27504)

* ci : add older, min and dry-run options to ccache-clear

Assisted-by: pi:llama.cpp/Qwen3.8-27B

* pi : add note about not wrapping lines in PR descriptions

[no ci]

Assisted-by: pi:llama.cpp/Qwen3.8-27B

.github/workflows/build-cpu.yml

@@ -117,6 +117,18 @@ jobs:
           ./bin/llama-convert-llama2c-to-ggml --copy-vocab-from-model ./tok512.bin --llama2c-model stories260K.bin --llama2c-output-model stories260K.gguf
           ./bin/llama-completion -m stories260K.gguf -p "One day, Lily met a Shoggoth" -n 500 -c 256
 
+      # note: real deletion only on push to master (same condition as the ccache save),
+      #       dry-run otherwise (the token is read-only on PRs from forks)
+      - name: ccache-clear
+        uses: ./.github/actions/ccache-clear
+        env:
+          GH_TOKEN: ${{ github.token }}
+        with:
+          key: cpu-${{ matrix.os }}
+          older: 1h
+          min: 1
+          dry-run: ${{ github.event_name != 'push' || github.ref != 'refs/heads/master' }}
+
   windows:
     name: windows / ${{ matrix.build }}
     runs-on: windows-2025