Add iOS app, SvelteKit JSON API endpoints, and Gitea CI workflow

- iOS SwiftUI app (ios/LibNovel/) targeting iOS 17+, generated via xcodegen
  - Full feature set: auth, home, library, book detail, chapter reader, browse, audio player, profile
  - Kingfisher for image loading, swift-markdown-ui for chapter rendering
  - Base URL: https://v2.libnovel.kalekber.cc
- SvelteKit JSON API routes (ui/src/routes/api/) for iOS consumption:
  auth/login, auth/register, auth/me, auth/logout, auth/change-password,
  home, library, book/[slug], chapter/[slug]/[n], search, ranking,
  progress/[slug], presign/audio (updated)
- Gitea Actions CI: .gitea/workflows/ios.yaml (build + test on macos-latest)
- justfile: ios-gen, ios-build, ios-test recipes

ui/src/routes/api/progress/[slug]/+server.ts

@@ -0,0 +1,34 @@
+import { json, error } from '@sveltejs/kit';
+import type { RequestHandler } from './$types';
+import { setProgress } from '$lib/server/pocketbase';
+import { log } from '$lib/server/logger';
+
+/**
+ * POST /api/progress/[slug]
+ * Body: { chapter: number }
+ * Records the user's reading position for a specific book.
+ *
+ * This is a slug-in-path variant of POST /api/progress (which takes slug in body).
+ * Used by the iOS app where slug is part of the URL path.
+ */
+export const POST: RequestHandler = async ({ params, request, locals }) => {
+	const { slug } = params;
+	const body = await request.json().catch(() => null);
+
+	if (!body || typeof body.chapter !== 'number') {
+		error(400, 'Invalid body — expected { chapter: number }');
+	}
+
+	try {
+		await setProgress(locals.sessionId, slug, body.chapter, locals.user?.id);
+	} catch (e) {
+		log.error('api/progress/[slug]', 'setProgress failed', {
+			slug,
+			chapter: body.chapter,
+			err: String(e)
+		});
+		error(500, 'Failed to save progress');
+	}
+
+	return json({ ok: true });
+};