feat: add profile management page with full CRUD UI

- Add frontend API layer, Pinia store, and 5 components (ProfileCard, ProfilesPanel, ProfileCreateModal, ProfileRenameModal, ProfileImportModal)
- Add ProfilesView page with card grid layout and expandable details
- Modify export endpoint to stream file as browser download instead of returning server path
- Add sidebar nav entry, router route, and i18n translations (en/zh)
- Support create, rename, delete, switch (with gateway restart), export, and import profiles

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

packages/client/src/components/layout/AppSidebar.vue

@@ -147,6 +147,27 @@ function handleNav(key: string) {
         <span>{{ t("sidebar.models") }}</span>
       </button>
 
+      <button
+        class="nav-item"
+        :class="{ active: selectedKey === 'hermes.profiles' }"
+        @click="handleNav('hermes.profiles')"
+      >
+        <svg
+          width="16"
+          height="16"
+          viewBox="0 0 24 24"
+          fill="none"
+          stroke="currentColor"
+          stroke-width="1.5"
+          stroke-linecap="round"
+          stroke-linejoin="round"
+        >
+          <path d="M20 21v-2a4 4 0 0 0-4-4H8a4 4 0 0 0-4 4v2" />
+          <circle cx="12" cy="7" r="4" />
+        </svg>
+        <span>{{ t("sidebar.profiles") }}</span>
+      </button>
+
       <button
         class="nav-item"
         :class="{ active: selectedKey === 'hermes.channels' }"