feat: composite actions + runner base image

Actions: checkout, setup-go, setup-node, setup-aws
Runner image: Go 1.26 + Node 22 + AWS CLI + Docker (docker:29-dind)

setup-node/action.yml

@@ -0,0 +1,39 @@
+name: 'Tinqs Setup Node'
+description: 'Install Node.js and pnpm (replaces actions/setup-node)'
+
+inputs:
+  node-version:
+    description: 'Node.js major version'
+    default: '22'
+  pnpm:
+    description: 'Install pnpm (true/false)'
+    default: 'true'
+
+runs:
+  using: 'composite'
+  steps:
+    - run: |
+        NODE_VERSION="${{ inputs.node-version }}"
+        INSTALL_PNPM="${{ inputs.pnpm }}"
+
+        # Skip if already installed at correct major version
+        if command -v node &>/dev/null; then
+          CURRENT=$(node --version | grep -oP '\d+' | head -1)
+          if [ "$CURRENT" = "$NODE_VERSION" ]; then
+            echo "Node $NODE_VERSION already installed"
+            node --version
+            [ "$INSTALL_PNPM" = "true" ] && command -v pnpm &>/dev/null && pnpm --version && exit 0
+          fi
+        fi
+
+        echo "Installing Node.js $NODE_VERSION..."
+        curl -fsSL "https://deb.nodesource.com/setup_${NODE_VERSION}.x" | bash -
+        apt-get install -y nodejs
+
+        if [ "$INSTALL_PNPM" = "true" ]; then
+          npm install -g pnpm
+          pnpm --version
+        fi
+
+        node --version
+      shell: bash