chore: bump starter version to 20260409 across Docker Compose examples

[rjvelazco]

Description

Updates CUSTOM_STARTER_URL across all Docker Compose example configurations from version 20260331 to 20260409, keeping them aligned with the latest UVE changes.

• Updated 10 Docker Compose files under docker/docker-compose-examples/
• Affected configurations: single-node, single-node-demo-site, single-node-debug-mode, cluster-mode, push-publish, with-opensearch-dashboard, with-redis, with-redis-session
• Most entries are commented out (used for local testing); only single-node-demo-site has the URL active by default

Linked Issues

Closes #35211

Testing

No functional changes — this only updates the starter bundle version referenced in Docker Compose example files. Manual verification: spin up single-node-demo-site and confirm it pulls the 20260409 starter.

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Note

Low Risk
Only updates example Docker Compose configuration values, mainly commented-out CUSTOM_STARTER_URLs, with no application code changes. Risk is limited to users relying on these examples pulling a different starter bundle.

Overview
Updates Docker Compose example configs to reference the 20260409 starter bundle instead of 20260331 via CUSTOM_STARTER_URL.

Most changes are commented example settings; single-node-demo-site/docker-compose.yml updates the active CUSTOM_STARTER_URL used by default.

^{Reviewed by Cursor Bugbot for commit 12ec8a8. Bugbot is set up for automated code reviews on this repo. Configure here.}

This PR fixes: #35211

[claude]

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Claude finished @rjvelazco's task in 33s —— View job

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I'll analyze this and get back to you.