feat: extract cms from mp/cms — initial libreshop/cms

Source moved verbatim from mp/cms/ on 2026-04-29; mp was the first
concrete adapter consuming the libreshop toolkit. Builds and publishes
git.librete.ch/libreshop/cms on every main / v* push via the standard
.gitea/workflows/build.yml shared across libreshop components.

config/api.ts

@@ -0,0 +1,7 @@
+export default {
+	rest: {
+		defaultLimit: 100,
+		maxLimit: 1_000,
+		withCount: true
+	}
+};