CI: Simplify verify action by leveraging packaged defaults

.forgejo/workflows/verify.yaml

@@ -17,57 +17,53 @@ jobs:
     timeout-minutes: 20
     container:
       image: rust:slim
-      env:
-        RUSTUP_HOME: /rust/rustup
-        CARGO_HOME: /rust/cargo
     steps:
       - name: Install action dependencies
         run: >
           apt-get install --no-install-recommends --update -y
-          nodejs git curl xz-utils
+          nodejs git xz-utils nix
 
       - name: Checkout code
         uses: actions/checkout@v6
         with:
           fetch-tags: true
 
+      - name: Cleanup checkout action dependencies
+        run: >
+          apt-get purge -y nodejs
+
+      - name: Set up CI user
+        run: |
+          useradd -m ci
+          chown -R ci:ci "$FORGEJO_WORKSPACE" /nix
+          printf '[safe]\ndirectory = %s\n' "$FORGEJO_WORKSPACE" \
+            > /etc/gitconfig
+
       - name: Set up Rust toolchain
         run: |
-          mkdir -p "$RUSTUP_HOME"
-          mkdir -p "$CARGO_HOME"
-
           rust_version=$(
               grep '^rust-version = "' Cargo.toml \
               | cut -d '"' -f 2
           )
 
-          rustup default "$rust_version"
-          rustup toolchain install nightly
-          rustup component add llvm-tools
-          rustup component add --toolchain nightly rustfmt clippy
-          rustup target add x86_64-unknown-linux-musl x86_64-unknown-linux-gnu
-
-      - name: Set up CI user
-        run: |
-          useradd -m ci
-          mkdir /nix
-          chown -R ci:ci "$RUSTUP_HOME" "$CARGO_HOME" "$PWD" /nix
-          printf '[safe]\ndirectory = %s\n' "$PWD" > /etc/gitconfig
+          su ci -c "
+            rustup default '$rust_version'
+            rustup toolchain install nightly
+            rustup component add llvm-tools
+            rustup component add --toolchain nightly rustfmt clippy
+            rustup target add \
+              x86_64-unknown-linux-musl \
+              x86_64-unknown-linux-gnu
+          "
 
       - name: Set up Nix
         run: |
-          mkdir /etc/nix
           echo experimental-features = nix-command flakes \
             >> /etc/nix/nix.conf
-          su ci -c "
-            sh -c 'curl -L https://nixos.org/nix/install |
-              bash -s -- --no-daemon' \
-          "
 
       - name: Assess
         run: |
-          su ci -lc "
-            export RUSTUP_HOME=$RUSTUP_HOME CARGO_HOME=$CARGO_HOME
+          ENV_PATH=$PATH su ci -c "
             nix develop path:$FORGEJO_WORKSPACE -c \
               just -f $FORGEJO_WORKSPACE/.justfile verify
           "