Add summary of metrics to landing page

Based on earlier discussions, it would be nice to display the following on the landing page to help assess a single run:
1. Number of unjudged docs (in top K)
2. Metrics with upper and lower bounds (based on assumptions about unjudged docs)

And to assess pairs of runs:
3. Wins/losses/draws between the two runs (e.g., number of queries with a > 0.01 difference in a metric)

No implementation files or tests are identified in the issue. Start by locating the landing-page entry point and the code that computes or presents run metrics, then determine how single-run bounds and pairwise wins, losses, and draws should be represented. Done means the landing page displays all three requested summaries for one run and for a pair of runs.

Written by the indexing model from the issue text.