chore(portal,operator): upgrade to Nuxt 4

Upgrade both Nuxt apps to Nuxt 4.4.6 (vue-tsc 3, TypeScript 5.6, undici 7) and add a root tsconfig.json to each app. Fix the strict-null / noUncheckedIndexedAccess errors surfaced by Nuxt 4's stricter generated tsconfig and vue-tsc 3. Drop the nuxt-oidc-auth pnpm patch (Nuxt 4 fixes the prepare:types crash natively).

apps/operator/pages/audit.vue

@@ -391,7 +391,7 @@ function fmtRelative(iso: string | null | undefined): string {
             <div class="cap">
               {{
                 archives?.length
-                  ? `archived through seq ${archives[0].endSeq} · ${archives.length} batch${archives.length === 1 ? '' : 'es'}`
+                  ? `archived through seq ${archives[0]!.endSeq} · ${archives.length} batch${archives.length === 1 ? '' : 'es'}`
                   : 'no archives yet · 90-day hot retention'
               }}
             </div>

apps/operator/pages/pricing.vue

@@ -209,7 +209,7 @@ const sortedPrices = computed<PriceRow[]>(() =>
             <td v-for="c in CURRENCIES" :key="c" class="cell-amount">
               <template v-if="drafts[row._id]">
                 <input
-                  v-model="drafts[row._id][c]"
+                  v-model="drafts[row._id]![c]"
                   type="text"
                   inputmode="decimal"
                   class="amount-input"