feat: publication management with cover images, PDFs, and fruit images (story #04)

Full CRUD for publications; link fruits to publications; upload per-fruit
PDF descriptions and fruit images stored as BYTEA; fruit detail page shows
publication descriptions and images. ImageOverlayDrawer for cover thumbnail
full-size view.

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

frontend/src/views/PublicationList.vue

@@ -0,0 +1,56 @@
+<script setup lang="ts">
+import { onMounted } from 'vue'
+import { usePublicationStore } from '../stores/publicationStore'
+
+const store = usePublicationStore()
+
+onMounted(async () => {
+  try {
+    await store.fetchPublications()
+  } catch {
+    // error already set in store
+  }
+})
+</script>
+
+<template>
+  <div class="mx-auto max-w-4xl p-6">
+    <div class="mb-4 flex items-center justify-between">
+      <h1 class="text-2xl font-bold">Publikationen</h1>
+      <router-link
+        to="/publications/new"
+        class="rounded bg-green-600 px-4 py-2 text-white hover:bg-green-700"
+      >
+        Neue Publikation
+      </router-link>
+    </div>
+
+    <div v-if="store.loading" class="text-gray-500">Lade…</div>
+    <div v-else-if="store.error" class="text-red-600">{{ store.error }}</div>
+    <div v-else-if="store.publications.length === 0" class="text-gray-500">
+      Keine Publikationen vorhanden.
+    </div>
+    <table v-else class="w-full border-collapse text-sm">
+      <thead>
+        <tr class="bg-gray-100 text-left">
+          <th class="border px-3 py-2">Titel</th>
+          <th class="border px-3 py-2">Autor</th>
+          <th class="border px-3 py-2">OSDB Kürzel</th>
+          <th class="border px-3 py-2"></th>
+        </tr>
+      </thead>
+      <tbody>
+        <tr v-for="pub in store.publications" :key="pub.id" class="hover:bg-gray-50">
+          <td class="border px-3 py-2">{{ pub.title }}</td>
+          <td class="border px-3 py-2">{{ pub.author ?? '—' }}</td>
+          <td class="border px-3 py-2 font-mono text-xs">{{ pub.osdb_pub_id }}</td>
+          <td class="border px-3 py-2">
+            <router-link :to="`/publications/${pub.id}`" class="text-blue-600 hover:underline">
+              Details
+            </router-link>
+          </td>
+        </tr>
+      </tbody>
+    </table>
+  </div>
+</template>