swarm ui: a pull requests card on the reports tab

The reports tab gets a "pull requests" card under the issue report. It lists
the open PRs of every repo, or of one picked in a repo select, with the
columns a reviewer or merger filters on: author, labels, requested
reviewers, base branch, WIP (the forge's draft flag), approvals against the
base branch's protection rule, has all approvals, conflicts, protected base
and CI. Every column sorts, the small-set columns filter by picking values,
and the browser keeps the filters and the repo. No filter applies at first.

swarm-controller resolves each row so the page makes no calls of its own:
GET /api/pr-report and GET /api/repos/{org}/{repo}/pr-report. The required
approvals come from the first matching branch protection rule (an
unprotected base asks for none); an approval counts when it is the
reviewer's latest decision, on the current head, neither stale nor
dismissed and official.

A free-text table cell gets a minimum width, so a table with many columns
scrolls sideways instead of wrapping a title to a word a line.

swarm-controller/src/main.rs

@@ -70,6 +70,7 @@ mod notify_flows;
 mod notify_router_api;
 mod observability_grant;
 mod otel_http_client;
+mod pr_report;
 mod proxy_credential;
 mod pulls;
 mod queue_identity;