Elastic Search After Support

[stefangutica]

Reasoning

• Added support for deep pagination using searchAfter to avoid large-offset pagination limitations.
• Aligned API behavior so searchAfter is used only on routes that actually reach Elastic list queries.
• Prepared the implementation for the Elastic package update where getList natively supports searchAfter.

Proposed Changes

• Propagated searchAfter through endpoint/service flows that reach elastic.indexer.service -> getList.
• Added per-item cursor support so each returned entity includes its own searchAfter (base64) value.
• Removed or avoided searchAfter on routes that do not use getList, to prevent misleading API behavior.
• Kept changes compatible with the upcoming Elastic package update for explicit getList(..., searchAfter) support.

How to test

• Call a getList-backed endpoint with size + searchAfter and verify the next page is returned correctly.
• Verify each returned entity item contains a valid searchAfter (base64) cursor.
• Confirm routes that do not use getList no longer rely on searchAfter.
• After upgrading the Elastic package, re-run pagination tests to validate native searchAfter forwarding on getList.