feat: Frontend gap closure — Schedules, Alerts, Migration, Changelog views

Implements missing frontend views and API integrations:

New Views:
- SchedulesView: CRUD for scheduled tasks (restart/announcement/command/plugin_reload)
- MigrationView: Export/import interface with file upload and history tracking
- ChangelogView: Paginated changelog feed with category badges
- ForgotPasswordView: Password reset flow with email submission
- AlertsView: Alert config dashboard with threshold settings and history

Component Updates:
- ErrorBoundary: Global error handler with retry functionality
- DashboardLayout: Mobile responsive sidebar, permission-based nav, new menu items
- ServerInfoView: Complete rewrite for public server info display

Infrastructure:
- useApi: Token refresh interceptor with 401 retry and infinite loop prevention
- plugins store: Implemented all stubbed methods with real API calls
- auth store: Added hasPermission() helper for RBAC UI visibility
- Router: Added new routes with catch-all fallback

Purpose: Closes frontend implementation gaps. Hardens auth flow, improves mobile UX,
enables server automation scheduling, alert configuration, and data migration tools.

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

frontend/src/views/admin/ChangelogView.vue

@@ -0,0 +1,112 @@
+<script setup lang="ts">
+import { ref, onMounted } from 'vue'
+import { useApi } from '@/composables/useApi'
+import { FileText, Tag, Loader2 } from 'lucide-vue-next'
+
+interface ChangelogEntry {
+  id: string
+  version: string
+  title: string
+  body: string
+  category: 'feature' | 'bugfix' | 'module' | 'security'
+  published_at: string
+}
+
+const api = useApi()
+const entries = ref<ChangelogEntry[]>([])
+const isLoading = ref(false)
+const page = ref(1)
+const hasMore = ref(true)
+
+async function fetchChangelog() {
+  isLoading.value = true
+  try {
+    const result = await api.get<ChangelogEntry[]>(`/changelog?page=${page.value}&limit=20`)
+    if (result.length === 0) {
+      hasMore.value = false
+    } else {
+      entries.value.push(...result)
+    }
+  } finally {
+    isLoading.value = false
+  }
+}
+
+function loadMore() {
+  page.value++
+  fetchChangelog()
+}
+
+function getCategoryColor(category: string): string {
+  switch (category) {
+    case 'feature': return 'bg-green-500/10 text-green-400'
+    case 'bugfix': return 'bg-red-500/10 text-red-400'
+    case 'module': return 'bg-blue-500/10 text-blue-400'
+    case 'security': return 'bg-yellow-500/10 text-yellow-400'
+    default: return 'bg-neutral-700/50 text-neutral-400'
+  }
+}
+
+onMounted(() => {
+  fetchChangelog()
+})
+</script>
+
+<template>
+  <div class="p-6 space-y-6">
+    <!-- Header -->
+    <div class="flex items-center gap-3">
+      <FileText class="w-5 h-5 text-oxide-500" />
+      <h1 class="text-2xl font-bold text-neutral-100">Changelog</h1>
+    </div>
+
+    <!-- Changelog Feed -->
+    <div class="space-y-4">
+      <div
+        v-for="entry in entries"
+        :key="entry.id"
+        class="bg-neutral-900 border border-neutral-800 rounded-lg p-5"
+      >
+        <div class="flex items-start justify-between mb-3">
+          <div class="flex items-center gap-3">
+            <div class="flex items-center gap-2 px-2 py-1 bg-oxide-500/10 border border-oxide-500/20 rounded-lg">
+              <Tag class="w-3 h-3 text-oxide-400" />
+              <span class="text-xs font-mono text-oxide-400">{{ entry.version }}</span>
+            </div>
+            <span
+              class="text-xs font-medium px-2 py-0.5 rounded-full capitalize"
+              :class="getCategoryColor(entry.category)"
+            >
+              {{ entry.category }}
+            </span>
+          </div>
+          <span class="text-xs text-neutral-500">{{ new Date(entry.published_at).toLocaleDateString() }}</span>
+        </div>
+        <h3 class="text-lg font-bold text-neutral-100 mb-2">{{ entry.title }}</h3>
+        <div class="text-sm text-neutral-300 whitespace-pre-line leading-relaxed">
+          {{ entry.body }}
+        </div>
+      </div>
+
+      <!-- Loading State -->
+      <div v-if="isLoading" class="flex justify-center py-6">
+        <Loader2 class="w-6 h-6 text-oxide-500 animate-spin" />
+      </div>
+
+      <!-- Load More -->
+      <div v-else-if="hasMore" class="flex justify-center">
+        <button
+          @click="loadMore"
+          class="px-4 py-2 text-sm font-medium text-neutral-300 bg-neutral-800 hover:bg-neutral-700 rounded-lg transition-colors"
+        >
+          Load More
+        </button>
+      </div>
+
+      <!-- End of List -->
+      <div v-else class="text-center py-6 text-sm text-neutral-500">
+        No more changelog entries
+      </div>
+    </div>
+  </div>
+</template>