GRM-51: fix: API resilience with retry, idempotent releases, and graceful Vikunja errors

scripts/ci/post_merge.py

@@ -116,13 +116,19 @@ def main(commit_msg: str, commit_sha: str) -> None:
         client.post_comment(vikunja_task_id, html)
         client.update_task(vikunja_task_id, done=True)
     except APIError as e:
-        raise click.ClickException(
+        # Vikunja is a project management tool — if it's down, the merge
+        # still succeeded. Warn but don't fail the post-merge workflow.
+        click.echo(
             _(
-                "Vikunja API error: HTTP {status} — {message}",
+                "Warning: Vikunja API error (HTTP {status}): {message}. "
+                "Task {task_id} was NOT updated. The merge succeeded — "
+                "please update the Vikunja task manually.",
                 status=e.status,
                 message=e.message,
+                task_id=task_id,
             )
-        ) from None
+        )
+        return
 
     click.echo(
         _(