Reconcile FurnitureData.json with items_base after import

After every single import, batch import and batch-regen, cross-check all
items_base rows against the local FurnitureData.json: entries whose
spriteId drifted are corrected to the DB id, and missing entries plus
real id conflicts are reported in the API/SSE response. Entries that are
missing entirely are counted (rebuilding them needs SWF/nitro metadata).

src/lib/services/furni-data.ts

@@ -1,5 +1,6 @@
 import { existsSync, promises as fs } from "node:fs";
 import path from "node:path";
+import { db, ItemsBase } from "@/lib/db";
 import {
 	getGamedataRoot,
 	getNitroFilesRoot,
@@ -442,3 +443,86 @@ export async function appendFurniEntriesBatch(
 		await writeFurniData(furniData as Record<string, unknown>);
 	});
 }
+
+export interface FurniDataReconcileResult {
+	/** Entries whose stale spriteId was corrected to the DB id. */
+	fixedIds: number;
+	/** items_base rows with no matching furnitype entry (need re-import). */
+	missing: number;
+	/** spriteIds used by a different classname in the file; left untouched. */
+	conflicts: number;
+}
+
+/**
+ * Cross-check every items_base row against the local FurnitureData.json and
+ * repair drift:
+ * - an entry matching the classname but carrying a stale spriteId is updated
+ *   to the DB id (items_base is authoritative);
+ * - rows missing entirely from the file are counted (they need a re-import
+ *   or batch-regen, since building an entry requires the SWF/nitro metadata);
+ * - genuine spriteId conflicts (id used by a different classname) are counted
+ *   but never auto-fixed.
+ */
+export async function reconcileFurniDataWithItemsBase(): Promise<FurniDataReconcileResult> {
+	return withFurniDataLock(async () => {
+		const rows = await db
+			.select({ id: ItemsBase.id, itemName: ItemsBase.itemName })
+			.from(ItemsBase);
+
+		const furniData = (await readFurniData()) as Record<
+			string,
+			{ furnitype: Array<Record<string, unknown>> }
+		>;
+
+		const byId = new Map<
+			number,
+			{ section: string; index: number; entry: Record<string, unknown> }
+		>();
+		const byClass = new Map<
+			string,
+			{ section: string; index: number; entry: Record<string, unknown> }
+		>();
+		for (const section of ["roomitemtypes", "wallitemtypes"] as const) {
+			const arr = furniData[section]?.furnitype ?? [];
+			for (let i = 0; i < arr.length; i++) {
+				const e = arr[i];
+				const id = Number(e?.id);
+				if (Number.isFinite(id) && id > 0 && !byId.has(id)) {
+					byId.set(id, { section, index: i, entry: e });
+				}
+				const cn = typeof e?.classname === "string" ? e.classname : "";
+				if (cn && !byClass.has(cn)) {
+					byClass.set(cn, { section, index: i, entry: e });
+				}
+			}
+		}
+
+		let fixedIds = 0;
+		let missing = 0;
+		let conflicts = 0;
+
+		for (const row of rows) {
+			const spriteId = row.id;
+			const existing = byId.get(spriteId);
+			if (existing) {
+				if (existing.entry.classname !== row.itemName) {
+					conflicts++;
+				}
+				continue;
+			}
+			const byName = byClass.get(row.itemName);
+			if (byName) {
+				byName.entry.id = spriteId;
+				byId.set(spriteId, byName);
+				fixedIds++;
+			} else {
+				missing++;
+			}
+		}
+
+		if (fixedIds > 0) {
+			await writeFurniData(furniData as Record<string, unknown>);
+		}
+		return { fixedIds, missing, conflicts };
+	});
+}