feat(teams): the slash-command seam, and the first command through it

Phase 7 of TEAMS.md. `api.registerSlashCommands` stops throwing: a module
registers a command's DEFINITION and its HANDLER together, the bot pulls the
definitions over the internal listener and runs none of our code, and the
handler executes here — forced by the bot container having no `modules` volume,
and the right boundary anyway.

Registration validates what Discord would reject as a batch (names, description
lengths, the four option types, required-before-optional), because the bot
registers the whole set in one PUT and a single bad entry costs every command
including the bot's own. Commands are not namespaced under their owner — there
is no dot in Discord's name grammar — so collisions are first-come with the
holder named.

The dispatcher is the access boundary: `linked` has no Discord equivalent, so
the platform-side permission default can only ever be advertising. It resolves
the actor by `auth_providers.kind` rather than the id slug, treats a banned
account as unlinked, bounds a handler under the bot's own timeout, and keeps
`ok` outside the envelope so a handler cannot forge it.

Liveness is asked at both the pull and the dispatch. The registries have no
removal path, so a module an operator disables at runtime would otherwise keep
a live handler behind a command Discord still advertises.

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

server/src/router/v1/internal/internal.routes.js

@@ -16,4 +16,20 @@ router.get(
   ctrl.getBotConfig,
 )
 
+// The slash-command seam (TEAMS.md §7.1). Both stay off the public API and out
+// of the OpenAPI document for the same reason /bot-config does: the caller is
+// the bot process on the private compose network, and `/internal/*` is not a
+// published contract.
+router.get(
+  '/commands',
+  // #swagger.ignore = true
+  ctrl.listCommands,
+)
+
+router.post(
+  '/commands/dispatch',
+  // #swagger.ignore = true
+  ctrl.dispatchCommand,
+)
+
 module.exports = router