[Refactor/Chore] Pagination skips rows with the same timestamp in 4 endpoints

Self Checks

• I have read the Contributing Guide and Language Policy.
• This is only for refactors or chores; if you would like to ask a question, please head to Discussions.
• I have searched for existing issues search for existing issues, including closed ones.
• I confirm that I am using English to submit this report, otherwise it will be closed.
• 【中文用户 & Non English User】请使用英语提交，否则会被关闭 ：）
• Please do not modify this template :) and fill in all the required fields.

Description

Many reports about the same bug came in recently. I put the reports together here.

On PostgreSQL, created_at saves only whole seconds. Rows saved in the same second get the same created_at. The endpoints below sort only by created_at and use < / > for the next page. Rows with the same created_at as the cursor are skipped. Some endpoints also use id != cursor.id, but < already removes the cursor row, so id != cursor.id does not help.

Details (main @ 570552c)

Issue	PR	Code	Condition
#43084 Conversation variables	#43087	services/conversation_service.py:282	created_at > cursor.created_at
#43134 Console Logs chat messages	#43146	controllers/console/app/message.py:479, :501	created_at < cursor.created_at, id != cursor.id
#43265 Workflow runs	#43266	repositories/sqlalchemy_api_workflow_run_repository.py:270	created_at < cursor.created_at, id != cursor.id
#43335 Service API / web app message history	#43336	services/message_service.py:156, :221	created_at < cursor.created_at, id != cursor.id

Written with help from Claude Opus 5.5.

Motivation

Users lose rows with no error. One issue for all 4 endpoints makes the PRs easy to track.

Additional Context

#43335 was first reported in #35996. PR #37896 for #35996 was closed because of merge conflicts.