feat(catalog-sync): report sources that can only be compared, not imported

The Habbo presets (and the other furnidata-only sources) carry no
`nitroBaseUrl`, so the clone importer's `${nitroBaseUrl}/${classname}.nitro`
download can never work against them — an `--import-new` run would have failed
for every single item instead of saying why. The SWF path that does work against
`images.habbo.com` lives in `furni-import.ts`, not in the clone importer this
CLI uses.

`stepImportNew` now skips those sources up-front, lists them under
"compared only" in the summary, and the menu prints the same warning when an
import step is chosen with such a source, pointing at the sources that do serve
bundles. Verified: Habbo (COM) reports compare-only, while Habboon and
VirtualCity list real candidates.

scripts/catalog-sync.ts

@@ -83,6 +83,22 @@ export interface ImportOutcome {
 	skipped: number;
 	failed: number;
 	failures: Array<{ classname: string; error: string }>;
+	/** Sources that were skipped because they cannot serve bundles. */
+	skippedSources: string[];
+}
+
+/**
+ * Whether a source can actually be imported from.
+ *
+ * The clone import downloads `${nitroBaseUrl}/${classname}.nitro` and gives up
+ * when that is not reachable. Habbo's own entries carry no nitro/icon base URLs
+ * (their furnidata is served, their assets are not), so they are compare-only:
+ * perfect for finding out what this hotel lacks, useless for actually fetching
+ * it. The SWF-based path that works against `images.habbo.com` lives in
+ * `furni-import.ts`, not in the clone importer this CLI uses.
+ */
+export function canImportBundles(source: SourceRef): boolean {
+	return Boolean(source.nitroBaseUrl?.trim());
 }
 
 export interface CatalogSyncFlags {
@@ -420,8 +436,16 @@ async function stepImportNew(
 		itemType: string;
 	}> = [];
 	let lastSource = "";
+	const skippedSources: string[] = [];
 
 	for (const source of sources) {
+		if (!canImportBundles(source)) {
+			log(
+				`! ${source.name} serves no .nitro bundles — it can be compared against, but nothing can be imported from it`,
+			);
+			skippedSources.push(source.name);
+			continue;
+		}
 		if (flags.importLimit > 0 && planned >= flags.importLimit) break;
 		const remaining = flags.importLimit
 			? flags.importLimit - planned
@@ -515,6 +539,7 @@ async function stepImportNew(
 		skipped,
 		failed,
 		failures: failures.slice(0, 25),
+		skippedSources,
 	};
 }
 
@@ -736,12 +761,12 @@ function printSummary(report: AuditReport, started: number): void {
 		console.log(
 			`  imported from source   ${outcome.imported} new (${outcome.skipped} already present, ${outcome.failed} failed)`,
 		);
+		if (outcome.skippedSources.length > 0)
+			console.log(
+				`  compared only          ${outcome.skippedSources.join(", ")} (no .nitro bundles to import from)`,
+			);
 		for (const failure of outcome.failures)
 			console.log(`    ${failure.classname}: ${failure.error}`);
-		if (outcome.failures.length > 0)
-			console.log(
-				`  import failures are per-item: a failed download never aborts the run.`,
-			);
 	}
 
 	if (report.missingFromSources.length > 0) {