feat(hunt): add public flag to hunts and implement hunt creation page

- Add 'public' boolean column to Hunt model with default true
- Update hunt admin UI to toggle 'public' flag
- Implement new hunt creation page with form supporting all hunt properties
- Add sidebar navigation item for hunt creation for authorized users
- Adjust home API to filter hunts by public flag only

app/pages/hunt/[huntSlug]/admin.vue

@@ -253,6 +253,7 @@ async function deleteImage() {
           clearable-icon="replay"
         />
         <VaCheckbox v-model="formData.cloned.value.virtual" label="Virtual" />
+        <VaCheckbox v-model="formData.cloned.value.public" label="Public" />
         <VaCheckbox
           v-model="formData.cloned.value.allowJoin"
           label="Allow Join"