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-go/action.yml

@@ -0,0 +1,30 @@
+name: 'Tinqs Setup Go'
+description: 'Install Go and configure PATH (replaces actions/setup-go)'
+
+inputs:
+  go-version:
+    description: 'Go version to install'
+    default: '1.26.2'
+
+runs:
+  using: 'composite'
+  steps:
+    - run: |
+        GO_VERSION="${{ inputs.go-version }}"
+
+        # Skip if already installed at correct version
+        if command -v go &>/dev/null; then
+          CURRENT=$(go version | grep -oP '\d+\.\d+\.\d+' || true)
+          if [ "$CURRENT" = "$GO_VERSION" ]; then
+            echo "Go $GO_VERSION already installed"
+            go version
+            exit 0
+          fi
+        fi
+
+        echo "Installing Go $GO_VERSION..."
+        curl -fsSL "https://go.dev/dl/go${GO_VERSION}.linux-amd64.tar.gz" | tar -C /usr/local -xz
+        echo "/usr/local/go/bin" >> "$GITHUB_PATH"
+        export PATH="/usr/local/go/bin:$PATH"
+        go version
+      shell: bash