fix: remove Node.js from actual path location on Act runner

The Act runner has Node 18 at /opt/acttoolcache/node/18.20.3/x64/bin/,
not at /usr/local/bin/. Use $(dirname "$(which node)") to find and
remove the actual binary location before installing Node 22.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitea/workflows/build-app.yml

@@ -25,10 +25,11 @@ jobs:
           NEED_INSTALL=false
           if command -v node >/dev/null 2>&1; then
             NODE_MAJOR=$(node --version | sed 's/v\([0-9]*\).*/\1/')
+            OLD_NODE_DIR=$(dirname "$(which node)")
             echo "Found Node.js $(node --version) at $(which node) (major: ${NODE_MAJOR})"
             if [ "$NODE_MAJOR" -lt 22 ]; then
               echo "Node.js ${NODE_MAJOR} is too old, removing before installing 22..."
-              sudo rm -f /usr/local/bin/node /usr/local/bin/npm /usr/local/bin/npx /usr/local/bin/corepack
+              sudo rm -f "${OLD_NODE_DIR}/node" "${OLD_NODE_DIR}/npm" "${OLD_NODE_DIR}/npx" "${OLD_NODE_DIR}/corepack"
               hash -r
               NEED_INSTALL=true
             fi