perf: enable source-specific asset downloads and make nitro/icon URLs optional

Import improvements:
- importSingleFurni now accepts sourceSwfBaseUrl, nitroBaseUrl, iconBaseUrl
  params to try source-specific asset downloads before falling back to
  the official Habbo CDN (images.habbo.com)
- Source-specific URL cascade:
  1. Try sourceSwfBaseUrl/hof_furni/{rev}/{name}.swf
  2. Try sourceNitroBaseUrl/{name}.nitro (pre-made nitro bundles)
  3. Fallback to images.habbo.com/dcr/hof_furni/{rev}/{name}.swf
- Same fallback chain for icon downloads
- Clone sources can now have empty nitroBaseUrl/iconBaseUrl (retro
  hotels without nitro support)
- Added VirtualCity source (verified SWF downloads via virtualc.nl/dcr)
- Added sourceSwfBaseUrl field to CloneSource interface
- Both batch and single import routes pass source params through
- Clone POST route accepts sourceSwfBaseUrl, makes nitro/icon optional
- Nitro fallback download tries .nitro files before SWF conversion

src/lib/services/clone-sources.ts

@@ -8,6 +8,16 @@ export interface CloneSource {
 	nitroBaseUrl: string;
 	iconBaseUrl: string;
 	hotel: string;
+	/**
+	 * Optional per-source base URL for downloading SWF files.
+	 * When set, the import service will try this URL before falling back
+	 * to the official Habbo CDN (images.habbo.com).
+	 *
+	 * Retro hotels often have their own dcr/hof_furni structure,
+	 * e.g. "https://virtualcity.nl/dcr" →
+	 * "https://virtualcity.nl/dcr/hof_furni/{revision}/{classname}.swf"
+	 */
+	sourceSwfBaseUrl?: string;
 }
 
 const KEY = "clone_sources";
@@ -124,6 +134,19 @@ export const DEFAULT_SOURCES: CloneSource[] = [
 		nitroBaseUrl: "https://www.habblet.city/nitro/bundled/furniture",
 		iconBaseUrl: "https://www.habblet.city/nitro/icons",
 		hotel: "com",
+		// Retro hotels may use their own SWF server (Habbo official CDN still has legacy files)
+		// This field enables per-source SWF/nitro/icon download base URL fallback
+		// The import service will try: sourceSwfBaseUrl > images.habbo.com
+		sourceSwfBaseUrl: "https://www.habblet.city/dcr",
+	},
+	{
+		id: "default-virtualcity",
+		name: "VirtualCity",
+		furnidataUrl: "https://virtualc.nl/gamedata/furnidata_json/1",
+		nitroBaseUrl: "https://virtualc.nl/nitro/bundled/furniture",
+		iconBaseUrl: "https://virtualc.nl/nitro/icons",
+		hotel: "com",
+		sourceSwfBaseUrl: "https://virtualc.nl/dcr",
 	},
 ];
 
@@ -149,6 +172,7 @@ export async function upsertSource(
 	src: Omit<CloneSource, "id"> & { id?: string },
 ): Promise<CloneSource> {
 	const sources = await listSources();
+	const swfBase = src.sourceSwfBaseUrl?.trim().replace(/\/+$/, "");
 	const entry: CloneSource = {
 		id: src.id || randomUUID(),
 		name: src.name.trim(),
@@ -156,6 +180,7 @@ export async function upsertSource(
 		nitroBaseUrl: src.nitroBaseUrl.trim().replace(/\/+$/, ""),
 		iconBaseUrl: src.iconBaseUrl.trim().replace(/\/+$/, ""),
 		hotel: (src.hotel ?? "").trim(),
+		sourceSwfBaseUrl: swfBase || undefined,
 	};
 	const idx = sources.findIndex((s) => s.id === entry.id);
 	if (idx >= 0) sources[idx] = entry;