Kestrel's Hall moves into the kit and onto the shared host

The landing page was a static page in the blog, served by the Yunohost
box through an nginx drop-in and an SSOwat rule. It now lives in
gamehall/site beside family.json, is served by Caddy on the shared host
with the games (gamehall/gamehall.caddy), and publishes with
gamehall/deploy.sh. Its share image is its own, not the blog's.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Jm2auWk6RP71CjaAb4FMoG

CONVENTIONS.md

@@ -66,8 +66,8 @@ README.
 - **The family list** in the about panel, *More games in Kestrel's Hall*,
   comes from `family.json` and its heading links to the family's landing
   page, gamehall.kestrelsnest.social. A new game is added to the kit's
-  `family.json` and given a card on that page in the blog repo; both are
-  hand-kept.
+  `family.json` and given a card on that page (`gamehall/` in the kit);
+  both are hand-kept.
 - **A move names the round it was made for.** The room counts rounds
   played (`resolved` in its view), and a page sends that count with each
   move; the server refuses a move whose count is behind, so a slow