Setting to limit number of workflow runs displayed in the sidebar

**Is your feature request related to a problem? Please describe.**
The current list of workflow runs in the sidebar can be very long and cluttered. I often only care about the most recent runs (e.g., the last 3) to check their status quickly.

**Describe the solution you'd like**
I would like a configuration setting (e.g., `github-actions.workflows.limit`) that allows me to define the number of latest runs shown per workflow in the sidebar. For example, setting it to `3` would only show the 3 most recent runs.

**Describe alternatives you've considered**
Currently, I have to scroll through a long list of history which is distracting.

**Additional context**
This would help keep the UI clean and focused on immediate feedback.

The issue does not name files, tests, or entry points. Start by locating the workflow-run sidebar rendering and the extension configuration declarations, then trace how runs are fetched and displayed. Done means a setting such as github-actions.workflows.limit restricts each workflow to its latest configured number of runs.

Written by the indexing model from the issue text.