fix: IREN/ASTS/IRE stuck-pending + corridor feature

Fix stuck adapter_queue jobs (ASTS/IRE/IREN stuck pending forever):

1. fetchSpec early-return paths (cooldown checks) now update job status
   to 'backoff' with last_attempt set and 30s backoff_until, instead of
   returning without any status change. Prevents jobs from being
   re-processed every drain cycle indefinitely.

2. Wrap adapter.fetchOne() in 30s Promise.race timeout. A hung HTTP
   request no longer blocks the entire per-source promise chain
   forever, preventing all subsequent jobs for that source.

Also includes corridor/confluence feature, tiered quote schedules,
cache improvements, and HoldingsBookView refinements.

app/src/components/SidebarNav.tsx

@@ -48,6 +48,7 @@ const SECTIONS: NavSection[] = [
       { label: "Screener", href: "/screener", navId: "screener" },
       { label: "Institutional", href: "/institutional", navId: "institutional" },
       { label: "Dealer Flow", href: "/dealer-flow", navId: "dealer-flow" },
+      { label: "Confluence", href: "/confluence", navId: "confluence" },
     ],
   },
   {