chore(frontend): introduce prettier + eslint and prune unused code

- Add Prettier 3 with prettier-plugin-organize-imports (sorts/removes unused imports)
- Add ESLint 10 flat config with typescript-eslint + eslint-plugin-vue + eslint-config-prettier
- Add root scripts: format, format:check, lint, lint:fix
- Reformat 257 files across admin-web, ops-web, desktop-client, packages
- Remove unused locals/exports flagged by --noUnusedLocals/--noUnusedParameters
- Fix duplicate localTabLabel key, surrogate-pair regex u-flag, NBSP literal in regex
- Skip server/ (Go) and apps/browser-extension/ (deprecated per ADR)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/admin-web/src/views/FeatureStubView.vue

@@ -1,37 +1,37 @@
 <script setup lang="ts">
-import { computed } from "vue";
-import { useRoute } from "vue-router";
-import { useI18n } from "vue-i18n";
+import { computed } from 'vue'
+import { useI18n } from 'vue-i18n'
+import { useRoute } from 'vue-router'
 
-const route = useRoute();
-const { t } = useI18n();
+const route = useRoute()
+const { t } = useI18n()
 
-const title = computed(() => t(String(route.meta.titleKey ?? "common.details")));
-const description = computed(() => t(String(route.meta.descriptionKey ?? "common.noData")));
+const title = computed(() => t(String(route.meta.titleKey ?? 'common.details')))
+const description = computed(() => t(String(route.meta.descriptionKey ?? 'common.noData')))
 </script>
 
 <template>
   <section class="stub-view">
     <div class="stub-view__hero">
-      <p class="eyebrow">{{ t("featureStub.eyebrow") }}</p>
+      <p class="eyebrow">{{ t('featureStub.eyebrow') }}</p>
       <h2>{{ title }}</h2>
       <p>{{ description }}</p>
     </div>
 
     <div class="stub-view__grid">
       <article class="stub-card">
-        <h3>{{ t("featureStub.currentStatus") }}</h3>
-        <p>{{ t("featureStub.currentStatusText") }}</p>
+        <h3>{{ t('featureStub.currentStatus') }}</h3>
+        <p>{{ t('featureStub.currentStatusText') }}</p>
       </article>
 
       <article class="stub-card">
-        <h3>{{ t("featureStub.nextPriority") }}</h3>
+        <h3>{{ t('featureStub.nextPriority') }}</h3>
         <p>{{ description }}</p>
       </article>
 
       <article class="stub-card">
-        <h3>{{ t("featureStub.integrationStrategy") }}</h3>
-        <p>{{ t("featureStub.integrationStrategyText") }}</p>
+        <h3>{{ t('featureStub.integrationStrategy') }}</h3>
+        <p>{{ t('featureStub.integrationStrategyText') }}</p>
       </article>
     </div>
   </section>