chore(ci): install actionlint from release binary (#43)

Install actionlint from GitHub release binaries using the same pattern
as zizmor, eliminating the Go toolchain dependency.

## Changes

- **copilot-setup-steps.yml**: Replace `go install` with `gh release
download` for actionlint
- **actionlint.yml**: Apply same installation method for consistency
- Remove "Add GOPATH to PATH" steps (no longer needed)

## Pattern

```yaml
- name: Install Actionlint
  env:
    TMP_DIR: ${{ runner.temp }}
    GH_TOKEN: ${{ github.token }}
  run: |
    set -euo pipefail
    tarball="$TMP_DIR/actionlint.tar.gz"
    gh release download --repo rhysd/actionlint --pattern "actionlint_*_linux_amd64.tar.gz" --output "$tarball"
    tar -xzf "$tarball" -C "$TMP_DIR"
    install -D "$TMP_DIR/actionlint" /usr/local/bin
    rm "$tarball" "$TMP_DIR/actionlint"
```

Downloads latest release automatically via wildcard pattern. Faster
(~30-60s saved vs compilation) and consistent with existing zizmor
installation.

> [!WARNING]
>
> <details>
> <summary>Firewall rules blocked me from connecting to one or more
addresses (expand for details)</summary>
>
> #### I tried to connect to the following addresses, but was blocked by
firewall rules:
>
> - `https://api.github.com/graphql`
> - Triggering command: `/usr/bin/gh gh release list --repo
rhysd/actionlint --limit 3` (http block)
> - `https://api.github.com/repos/rhysd/actionlint/releases/latest`
>   - Triggering command: `/usr/bin/curl curl -s REDACTED` (http block)
>   - Triggering command: `/usr/bin/curl curl -sL REDACTED` (http block)
> - Triggering command: `/usr/bin/gh gh release view --repo
rhysd/actionlint --json assets --jq .assets[].name` (http block)
>
> If you need me to access, download, or install something from one of
these locations, you can either:
>
> - Configure [Actions setup
steps](https://gh.io/copilot/actions-setup-steps) to set up my
environment, which run before the firewall is enabled
> - Add the appropriate URLs or hosts to the custom allowlist in this
repository's [Copilot coding agent
settings](https://github.com/Garbee/runner-resource-usage/settings/copilot/coding_agent)
(admins only)
>
> </details>

<!-- START COPILOT CODING AGENT TIPS -->
---

✨ Let Copilot coding agent [set things up for
you](https://github.com/Garbee/runner-resource-usage/issues/new?title=✨+Set+up+Copilot+instructions&body=Configure%20instructions%20for%20this%20repository%20as%20documented%20in%20%5BBest%20practices%20for%20Copilot%20coding%20agent%20in%20your%20repository%5D%28https://gh.io/copilot-coding-agent-tips%29%2E%0A%0A%3COnboard%20this%20repo%3E&assignees=copilot)
— coding agent works faster and does higher quality work when set up for
your repo.

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Garbee <868301+Garbee@users.noreply.github.com>

Author: Copilot

.github/workflows/actionlint.yml

@@ -30,10 +30,17 @@ jobs:
           persist-credentials: false
       - name: Start Workflow Telemetry
         uses: ./
-      - name: Install actionlint
-        run: go install github.com/rhysd/actionlint/cmd/actionlint@latest
-      - name: Add GOPATH to PATH
-        run: echo "$HOME/go/bin" >> "$GITHUB_PATH"
+      - name: Install Actionlint
+        env:
+          TMP_DIR: ${{ runner.temp }}
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          set -euo pipefail
+          tarball="$TMP_DIR/actionlint.tar.gz"
+          gh release download --repo rhysd/actionlint --pattern "actionlint_*_linux_amd64.tar.gz" --output "$tarball"
+          tar -xzf "$tarball" -C "$TMP_DIR"
+          install -D "$TMP_DIR/actionlint" /usr/local/bin
+          rm "$tarball" "$TMP_DIR/actionlint"
       - name: Check Workflow Files
         run: actionlint -format "$(cat .github/formatters/actionlint-sarif.gotmpl)" .github/workflows/*.yml > actionlint.sarif
       - name: Upload SARIF File

.github/workflows/copilot-setup-steps.yml

@@ -54,9 +54,16 @@ jobs:
       - name: Install Dependencies
         run: npm ci
       - name: Install Actionlint
-        run: go install github.com/rhysd/actionlint/cmd/actionlint@latest
-      - name: Add GOPATH to PATH
-        run: echo "$HOME/go/bin" >> "$GITHUB_PATH"
+        env:
+          TMP_DIR: ${{ runner.temp }}
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          set -euo pipefail
+          tarball="$TMP_DIR/actionlint.tar.gz"
+          gh release download --repo rhysd/actionlint --pattern "actionlint_*_linux_amd64.tar.gz" --output "$tarball"
+          tar -xzf "$tarball" -C "$TMP_DIR"
+          install -D "$TMP_DIR/actionlint" /usr/local/bin
+          rm "$tarball" "$TMP_DIR/actionlint"
       - name: Install Zizmor
         env:
           TMP_DIR: ${{ runner.temp }}