fix: Alpine compatibility + READMEs + roadmap

- setup-node: detect Alpine/Debian, use apk or NodeSource
- setup-aws: use pip on Alpine (musl), binary on Debian (glibc)
- setup-go: fix version parsing for Alpine (no grep -P)
- README per action with usage examples and input docs
- PLAN.md: roadmap for runner images, labels, Lambda dispatch

setup-node/README.md

@@ -0,0 +1,27 @@
+# tinqs/ci/setup-node
+
+Installs Node.js and optionally pnpm.
+
+Detects Alpine vs Debian and uses the right package manager (`apk` or NodeSource). Skips installation if the correct major version is already present in the runner image.
+
+## Usage
+
+```yaml
+- uses: tinqs/ci/setup-node@v1
+```
+
+### Options
+
+```yaml
+- uses: tinqs/ci/setup-node@v1
+  with:
+    node-version: '22'    # default: 22
+    pnpm: 'true'          # default: true
+```
+
+## Inputs
+
+| Input | Default | Description |
+|-------|---------|-------------|
+| `node-version` | `22` | Node.js major version |
+| `pnpm` | `true` | Install pnpm globally |