feat: AniList reading status integration

- Add full AniList integration: OAuth connect, series linking, push/pull sync
- Push: PLANNING/CURRENT/COMPLETED based on books read vs total_volumes (never auto-complete from owned books alone)
- Pull: update local reading progress from AniList list (per-user)
- Detailed sync/pull reports with per-series status and progress
- Local user selector in settings to scope sync to a specific user
- Rename "AniList" tab/buttons to generic "État de lecture" / "Reading status"
- Make Bédéthèque and AniList badges clickable links on series detail page
- Fix ON CONFLICT error on series link (provider column in PK)
- Migration 0054: fix series_metadata missing columns (authors, publishers, locked_fields, total_volumes, status)
- Align button heights on series detail page; move MarkSeriesReadButton to action row

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

apps/backoffice/app/api/anilist/search/route.ts

@@ -0,0 +1,16 @@
+import { NextResponse, NextRequest } from "next/server";
+import { apiFetch } from "@/lib/api";
+
+export async function POST(request: NextRequest) {
+  try {
+    const body = await request.json();
+    const data = await apiFetch("/anilist/search", {
+      method: "POST",
+      body: JSON.stringify(body),
+    });
+    return NextResponse.json(data);
+  } catch (error) {
+    const message = error instanceof Error ? error.message : "Failed to search AniList";
+    return NextResponse.json({ error: message }, { status: 500 });
+  }
+}