Read every route from the routing table in memory (part of #122)

The IP lookups, the AS and prefix pages and their API answers, the prefix-length pages and the stats read routes only from the routing table the prefix handler keeps. fx reads the table at startup and gives it to both. AS names, WHOIS details and first-seen times still come from the database.

The IP lookup names the origin AS most peers carry, with the time of the newest kept route. The prefix answers list peers whose routes are not kept without a path or time. The stats gain origins_without_kept_route. They no longer read route times from the per-peer tables, so the two helpers that did are gone.

Model: opus-5-5

TODO.md

@@ -33,6 +33,12 @@ tested.
 
 # Completed Steps
 
+- 2026-10-27: the pages, the API and the stats read every route from the routing
+  table in memory. For a prefix with several origin ASes, the IP lookup gives
+  the one most peers carry. Its `last_seen` is the newest kept route's time. The
+  prefix page and API list every peer that carries the prefix, with an AS path,
+  next hop and time only for the kept routes. The stats count the origins whose
+  kept routes were all withdrawn, in `origins_without_kept_route` (part of #122)
 - 2026-10-27: the prefix, AS and peer handlers make a timed write on every tick
   of their timers, every 1, 2 and 2 seconds. They used to skip every other tick.
   A full batch's write restarts the timer, so the next timed write comes one
@@ -271,6 +277,5 @@ tested.
 
 # Future Steps
 
-- the rest of https://git.eeqj.de/sneak/routewatch/issues/122, one PR each: the
-  pages and the API reading from the routing table, then removing the per-peer
-  route tables
+- the rest of https://git.eeqj.de/sneak/routewatch/issues/122: removing the
+  per-peer route tables