feat(ci): nix cache for staging and testnet-internal

.github/workflows/nix-cache.yml

@@ -0,0 +1,71 @@
+name: Nix Cache
+
+on:
+  workflow_dispatch:
+  push:
+    # Only build nix cache for branches that need distribution
+    branches: [ "staging", "testnet-internal", "o/nix-ci" ]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  # build & cache project dependencies
+  deps:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v25
+    - uses: cachix/cachix-action@v14
+      with:
+        name: fleek-network
+        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+    - run: nix build .#lightning-deps
+
+  # build & cache node binary
+  node:
+    runs-on: ubuntu-latest
+    needs: deps
+    steps:
+    - name: Clean runner image
+      run: |
+        # Free up some space, we only need nix anyways
+        df -h
+        sudo rm -rf \
+          "$AGENT_TOOLSDIRECTORY" \
+          /usr/local/share/boost \
+          /usr/share/dotnet \
+          /opt/ghc
+        echo "After removing files:"
+        df -h
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v25
+    - uses: cachix/cachix-action@v14
+      with:
+        name: fleek-network
+        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+    - run: nix build .#lightning-node
+
+  # build & cache services binaries
+  services:
+    runs-on: ubuntu-latest
+    needs: deps
+    steps:
+    - name: Clean runner image
+      run: |
+        # Free up some space, we only need nix anyways
+        df -h
+        sudo rm -rf \
+          "$AGENT_TOOLSDIRECTORY" \
+          /usr/local/share/boost \
+          /usr/share/dotnet \
+          /opt/ghc
+        echo "After removing files:"
+        df -h
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v25
+    - uses: cachix/cachix-action@v14
+      with:
+        name: fleek-network
+        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+    - run: nix build .#lightning-services