fix: replace ToS-blocked maintain-one-comment with marocchino sticky comment (#75)

actions-cool/maintain-one-comment was blocked by GitHub for a Terms of
Service violation on 2026-05-19. The Actions runner can no longer download
it, so every workflow resolving it fails at prep with "Repository access
blocked". This broke the ephemeral instance preview flow (the only path
using the action) while ci.yml kept passing.

Swap all three usages (prepare, finish, ephemeral/shutdown) to the
maintained marocchino/sticky-pull-request-comment (SHA-pinned, v3.0.4).
The shared `header: localstack-preview` preserves the single-sticky-comment
behaviour across the create/update/shutdown lifecycle; marocchino manages
its own hidden marker, so the literal HTML marker line is dropped. The
"Preview for this PR" text asserted by the ephemeral test is preserved.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: plafond

ephemeral/shutdown/action.yml

@@ -69,11 +69,10 @@ runs:
         retry shutdown_instance
     
     - name: Update status comment
-      uses: actions-cool/maintain-one-comment@4b2dbf086015f892dcb5e8c1106f5fccd6c1476b # v3
+      uses: marocchino/sticky-pull-request-comment@0ea0beb66eb9baf113663a64ec522f60e49231c0 # v3.0.4
       with:
-        token: ${{ inputs.github-token }}
-        body: |
-          The ephemeral instance for the application preview has been shut down
-          <!-- Sticky Pull Request Comment -->
-        body-include: '<!-- Sticky Pull Request Comment -->'
+        GITHUB_TOKEN: ${{ inputs.github-token }}
+        header: localstack-preview
         number: ${{ steps.pr.outputs.pr_id }}
+        message: |
+          The ephemeral instance for the application preview has been shut down

finish/action.yml

@@ -71,12 +71,11 @@ runs:
         fi
 
     - name: Update status comment
-      uses: actions-cool/maintain-one-comment@4b2dbf086015f892dcb5e8c1106f5fccd6c1476b # v3
+      uses: marocchino/sticky-pull-request-comment@0ea0beb66eb9baf113663a64ec522f60e49231c0 # v3.0.4
       with:
-        token: ${{ inputs.github-token }}
-        body: |
+        GITHUB_TOKEN: ${{ inputs.github-token }}
+        header: localstack-preview
+        number: ${{ steps.pr.outputs.pr_id }}
+        message: |
           ${{ inputs.ci-project && format('{0}{1}', '🚀 LocalStack Stack Insights and Cloud Pod state for this CI run: https://app.localstack.cloud/ci/', inputs.ci-project) }}
           ${{ inputs.include-preview && format('{0}{1}', '🚀 Preview for this PR: ', env.LS_PREVIEW_URL) }}
-          <!-- Sticky Pull Request Comment -->
-        body-include: '<!-- Sticky Pull Request Comment -->'
-        number: ${{ steps.pr.outputs.pr_id }}

prepare/action.yml

@@ -23,10 +23,9 @@ runs:
         path: ./pr-id.txt
 
     - name: Create initial PR comment
-      uses: actions-cool/maintain-one-comment@4b2dbf086015f892dcb5e8c1106f5fccd6c1476b # v3
+      uses: marocchino/sticky-pull-request-comment@0ea0beb66eb9baf113663a64ec522f60e49231c0 # v3.0.4
       with:
-        token: ${{ inputs.github-token }}
-        body: |
+        GITHUB_TOKEN: ${{ inputs.github-token }}
+        header: localstack-preview
+        message: |
           ⚡️ Running CI build with LocalStack ...
-          <!-- Sticky Pull Request Comment -->
-        body-include: '<!-- Sticky Pull Request Comment -->'