Runs that finished without a push, comment or failure leave the timeline and show as one "N quiet runs" line #5813

For #5735's "more concise and direct": a run that changed nothing is noise above the posts that matter.

Done when:

• [ ] A run.finished post that is not failed, not a cost post, and whose run made no push, pull, comment or issue is left out of the timeline. The feed reads that from the run's own record.
• [ ] One line at the end of the feed's first page says N quiet runs in the last 24 h, linking to the runs list.
• [ ] The chip counts and cursor paging stay correct. A test seeds 5 quiet runs and 2 that pushed, and finds 2 posts and 5 quiet runs.
• [ ] MCP feed leaves the same runs out and gives quietRuns: N.