feat: Dispo V2 import — API router + admin UI

API Router (packages/api/src/router/dispo.ts):
- 12 adminProcedure endpoints wired to existing application layer
- stageImportBatch, validateImportBatch, commitImportBatch
- listImportBatches, getImportBatch, cancelImportBatch
- listStagedResources/Projects/Assignments/Vacations/Unresolved
- resolveStagedRecord (APPROVE/REJECT/SKIP actions)

Admin UI:
- /admin/dispo-imports — batch list with status filter, new import modal
- /admin/dispo-imports/[batchId] — detail with 6 tabs:
  Summary, Resources, Projects, Assignments, Vacations, Unresolved
- Unresolved review queue with approve/skip per-record actions
- Commit workflow with pre-validation and progress indicator
- Sidebar nav link under Admin

Also fixes: timeline filter dropdown z-index (toolbar relative z-20)

Co-Authored-By: claude-flow <ruv@ruv.net>

apps/web/src/app/(app)/admin/dispo-imports/[batchId]/page.tsx

@@ -0,0 +1,10 @@
+import { DispoImportDetailClient } from "~/components/admin/DispoImportDetailClient.js";
+
+export default async function DispoImportDetailPage({
+  params,
+}: {
+  params: Promise<{ batchId: string }>;
+}) {
+  const { batchId } = await params;
+  return <DispoImportDetailClient batchId={batchId} />;
+}

apps/web/src/app/(app)/admin/dispo-imports/page.tsx

@@ -0,0 +1,5 @@
+import { DispoImportClient } from "~/components/admin/DispoImportClient.js";
+
+export default function DispoImportsPage() {
+  return <DispoImportClient />;
+}