feat(glossy): add type-checking

- adds type-checking via the valkyrie package
- fixes handling of groups parameter on #glossary()
- new test for relevant changes

glossy/src/schemas.typ

@@ -0,0 +1,26 @@
+// TODO: change to @preview when online
+#import "@preview/valkyrie:0.2.1" as z
+
+#let dict-schema = z.either(
+  z.string(),
+  z.dictionary(
+    (
+      short: z.content(), // this is the only required field
+      plural: z.content(optional: true),
+      long: z.content(optional: true),
+      longplural: z.content(optional: true),
+      description: z.content(optional: true),
+      group: z.content(optional: true),
+    )
+  )
+)
+
+#let theme-schema = z.dictionary(
+  (
+    section: z.function(),
+    group: z.function(),
+    entry: z.function(),
+  )
+)
+
+#let groups-list-schema = z.array(pre-transform: z.coerce.array)