feat(guilds): a guild detail page, and the slot core puts the feed in

The module's half of the org lead's correction: Teams is the contract, guilds
are the presentation, and the presentation is this module's.

Adds `/uo/guilds/:id` — the detail view the board never had — with the roster
from this module's OWN board, which is the same data it answers core's Team
provider from. Reading core's projection of our own answer back would be a round
trip through a staler copy of it.

The page declares `uo.guild.detail` and core fills it with the Team activity
feed. That is the one part of this page core cannot hand over: only core can
resolve whether the viewer is inside the Team, and the public/members split on
that feed is a security boundary. The guild is named in OUR terms — core maps
its own Team from the module id and the external id — so this module never holds
core's row id or slug.

`TeamOverviewStrip` is deleted with the core Team page it filled.
`team.member.row` is not declared here either: the useful thing to put in a
roster row is a link to the character behind it, and nothing core could supply
identifies one.

`GET /public/shard/guilds/:id` backs the page, gated and projected through the
same `guilds` feature as the board — so an operator who raises that audience
raises this too, and the locked acct/webId fields never survive below admin. A
roster is where those appear in bulk, which makes this the endpoint where
getting the projection wrong would matter most.

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

client/src/core.js

@@ -48,7 +48,7 @@ if (createElement !== rg.react.createElement || createRoot !== rg.reactDom.creat
   )
 }
 
-// The curated kit (§3.4). Seven members, closed: anything else this module needs
+// The curated kit (§3.4). Eight members, closed: anything else this module needs
 // it bundles itself, which is why `components/` next door exists at all.
 export const {
   PublicLayout,
@@ -59,6 +59,11 @@ export const {
   useAsync,
   useAuth,
   useSite,
+  // Eighth member (MODULE_API 1.6.0): the slot renderer, for the INVERTED
+  // direction — this module declares a place on its own page and CORE fills it.
+  // Shared rather than reimplemented so core's content failing inside our page is
+  // contained by core's own error boundary.
+  Slot,
 } = rg.ui
 
 // The registry, for entry.jsx. Everything else here is read by pages.