Dashboard runs: use page_size param once backend supports it

[Mbeaulne]

Summary

Once TangleML/tangle#188 lands, update RunSection to pass a page_size query param to the backend so the number of fetched rows matches what the viewport can display.

Motivation

The Dashboard homepage currently uses maxItems to slice backend results client-side. This means we always over-fetch and page tokens skip sliced items. Passing page_size will make fetches exact and pagination correct.

Changes Needed

• Add pageSize?: number prop to RunSection
• Pass it as page_size query param in the fetch URL (alongside page_token, filter_query, etc.)
• Update DashboardHomeView and DashboardRunsView to pass dynamicRows as pageSize instead of maxItems
• Remove maxItems slicing once pageSize is wired up

Depends On

• feat: [BE] Add page_size param to pipeline runs list endpoint tangle#188

Related

• Part of epic: epic: Homepage Redesign #1964