Clarify where setup-trunk puts the Trunk binary

.forgejo/setup-trunk/action.yaml

@@ -10,8 +10,13 @@ runs:
   using: "composite"
   steps:
     - run: rustup target add wasm32-unknown-unknown
-    # Assume we remain in the top-level directory of the checkout:
+    
+    # install the Trunk binary to `ci-bin` within the workspace directory, which
+    # is determined by the `github.workspace` label and reflected in the
+    # `GITHUB_WORKSPACE` environment variable. then, make the `trunk` command
+    # available by placing the fully qualified path to `ci-bin` on the
+    # workflow's search path
     - run: mkdir -p ci-bin
     - run: curl --output - --proto '=https' --tlsv1.2 --retry 10 --retry-connrefused --location --silent --show-error --fail 'https://github.com/trunk-rs/trunk/releases/download/v0.21.12/trunk-x86_64-unknown-linux-gnu.tar.gz' | tar --gunzip --extract --file -
       working-directory: ci-bin
-    - run: echo "$(pwd)/ci-bin" >> $GITHUB_PATH
+    - run: echo "${{ github.workspace }}/ci-bin" >> $GITHUB_PATH

.forgejo/workflows/continuous-integration.yaml

@@ -14,8 +14,18 @@ jobs:
       image: cimg/rust:1.85-node
     defaults:
       run:
+        # set the default working directory for each `run` step, relative to the
+        # workspace directory. this default only affects `run` steps (and if we
+        # tried to set the `working-directory` label for any other kind of step,
+        # it wouldn't be recognized anyway)
         working-directory: app-proto
     steps:
+      # check out the repository to the workspace directory. in the action
+      # description, you can get and set the workspace directory through the
+      # `github.workspace` and `env.GITHUB_WORKSPACE` labels, which always have
+      # the same value. in the container, you can get the workspace directory
+      # from the `GITHUB_WORKSPACE` environment variable
       - uses: https://code.forgejo.org/actions/checkout@v4
+      
       - uses: ./.forgejo/setup-trunk
       - run: RUSTFLAGS='-D warnings' cargo test