fix(bots): guard possibly-undefined route param, bump arena image to 1.2.11

tsc --noEmit (run standalone, not filtered through a shell wrapper that
silently swallowed the real exit code) caught what my own verification
missed the first time: c.req.param('name') is typed possibly-undefined
in this Hono router's inferred route map, and the podman build's own
`pnpm --filter server build` step (which runs the real tsc, unlike a
loosely-configured local check) failed on it — 1.2.10 was never
actually built with the :name/ai-config routes as a result. Added an
explicit guard (matches the 404 semantics of a missing param) to all
three new handlers.

Also bumps docker-compose.arena.yml to the 1.2.11 tag being built next.

Co-Authored-By: Claude <noreply@anthropic.com>

docker-compose.arena.yml

@@ -18,7 +18,7 @@
 
 services:
   botfights-arena:
-    image: localhost:3000/lfg2025/botfights:1.2.9
+    image: localhost:3000/lfg2025/botfights:1.2.11
     container_name: botfights-arena
     restart: unless-stopped
     ports: