fix: dnf support in setup-node + setup-aws, node label t3.medium

- setup-node: detect dnf (Amazon Linux) alongside apk/apt-get
- setup-aws: detect dnf for official installer
- node Spot bumped to t3.medium (4GB) — Docusaurus OOM'd on t3.small

setup-node/action.yml

@@ -1,7 +1,7 @@
 # tinqs/ci/setup-node — Tinqs Studio CI
 # Installs Node.js and optionally pnpm.
-# Detects Alpine vs Debian and uses the right package manager.
-# Skips install if the correct major version is already present (pre-baked runner image).
+# Detects Alpine (apk), Debian (apt-get), and Amazon Linux/RHEL (dnf).
+# Skips install if the correct major version is already present (pre-baked AMI).
 # Composite action — runs directly on the host.
 # Author: Ozan + Claude Code — 2026-05-22
 
@@ -29,10 +29,17 @@ runs:
           if [ "$CURRENT" = "$NODE_VERSION" ]; then
             echo "Node $NODE_VERSION already installed"
             node --version
-            if [ "$INSTALL_PNPM" = "true" ] && command -v pnpm &>/dev/null; then
-              pnpm --version
-              exit 0
+            if [ "$INSTALL_PNPM" = "true" ]; then
+              if command -v pnpm &>/dev/null; then
+                pnpm --version
+                exit 0
+              else
+                npm install -g pnpm
+                pnpm --version
+                exit 0
+              fi
             fi
+            exit 0
           fi
         fi
 
@@ -40,6 +47,10 @@ runs:
         if command -v apk &>/dev/null; then
           # Alpine
           apk add --no-cache nodejs npm
+        elif command -v dnf &>/dev/null; then
+          # Amazon Linux / RHEL / Fedora
+          curl -fsSL "https://rpm.nodesource.com/setup_${NODE_VERSION}.x" | bash -
+          dnf install -y nodejs
         elif command -v apt-get &>/dev/null; then
           # Debian/Ubuntu
           curl -fsSL "https://deb.nodesource.com/setup_${NODE_VERSION}.x" | bash -