Improve admin candidate modal UX and add clip menu visibility toggle

- Widen AdminCandidateEditorModal to size lg for better readability
- Rename "Clip-Compilation" section to "Clip / Compilation", update copy to reflect single clips too, drop upload hint and Clip-Plattform field, rename label to "Link"
- Fix NativeSelect dropdown clipping inside overflow-y-auto modals by teleporting the menu to body with fixed positioning, flip-up logic, and dynamic maxHeight capped to viewport
- Add ClipAdminMenuVisible setting (backend domain, contracts, endpoint, migration) with matching frontend types, defaults, form wiring, and toggle in the Clip-Workflow modal — hides the Clips nav item from the admin sidebar when disabled

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/home/HomeWizardFooter.vue

@@ -0,0 +1,36 @@
+<script setup lang="ts">
+export interface HomeWizardFooterAction {
+  label: string
+  disabled?: boolean
+  tone?: 'primary' | 'secondary' | 'danger'
+  onClick: () => Promise<void> | void
+}
+
+const props = defineProps<{
+  progressText: string
+  helperText: string
+  actions: HomeWizardFooterAction[]
+}>()
+</script>
+
+<template>
+  <footer class="home-wizard-footer">
+    <div class="home-wizard-footer__copy">
+      <strong>{{ props.progressText }}</strong>
+      <span>{{ props.helperText }}</span>
+    </div>
+    <div class="home-wizard-footer__actions">
+      <button
+        v-for="action in props.actions"
+        :key="action.label"
+        type="button"
+        class="home-wizard-footer__button"
+        :class="`home-wizard-footer__button--${action.tone ?? 'primary'}`"
+        :disabled="action.disabled"
+        @click="action.onClick"
+      >
+        {{ action.label }}
+      </button>
+    </div>
+  </footer>
+</template>