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/auth/register/+server.ts

@@ -0,0 +1,84 @@
+import { json, error } from '@sveltejs/kit';
+import type { RequestHandler } from './$types';
+import { createUser, mergeSessionProgress, createUserSession } from '$lib/server/pocketbase';
+import { createAuthToken } from '../../../../hooks.server';
+import { log } from '$lib/server/logger';
+import { randomBytes } from 'node:crypto';
+
+const AUTH_COOKIE = 'libnovel_auth';
+const ONE_YEAR = 60 * 60 * 24 * 365;
+
+/**
+ * POST /api/auth/register
+ * Body: { username: string, password: string }
+ * Returns: { token: string, user: { id, username, role } }
+ *
+ * Sets the libnovel_auth cookie and returns the raw token value so the
+ * iOS app can persist it for subsequent requests.
+ */
+export const POST: RequestHandler = async ({ request, cookies, locals }) => {
+	let body: { username?: string; password?: string };
+	try {
+		body = await request.json();
+	} catch {
+		error(400, 'Invalid JSON body');
+	}
+
+	const username = (body.username ?? '').trim();
+	const password = body.password ?? '';
+
+	if (!username || !password) {
+		error(400, 'Username and password are required');
+	}
+	if (username.length < 3 || username.length > 32) {
+		error(400, 'Username must be between 3 and 32 characters');
+	}
+	if (!/^[a-zA-Z0-9_-]+$/.test(username)) {
+		error(400, 'Username may only contain letters, numbers, underscores and hyphens');
+	}
+	if (password.length < 8) {
+		error(400, 'Password must be at least 8 characters');
+	}
+
+	let user;
+	try {
+		user = await createUser(username, password);
+	} catch (e: unknown) {
+		const msg = e instanceof Error ? e.message : 'Registration failed.';
+		if (msg.includes('Username already taken')) {
+			error(409, 'That username is already taken');
+		}
+		log.error('api/auth/register', 'unexpected error', { username, err: String(e) });
+		error(500, 'An error occurred. Please try again.');
+	}
+
+	// Merge anonymous session progress (non-fatal)
+	mergeSessionProgress(locals.sessionId, user.id).catch((e) =>
+		log.warn('api/auth/register', 'mergeSessionProgress failed (non-fatal)', { err: String(e) })
+	);
+
+	const authSessionId = randomBytes(16).toString('hex');
+
+	const userAgent = request.headers.get('user-agent') ?? '';
+	const ip =
+		request.headers.get('x-forwarded-for')?.split(',')[0]?.trim() ??
+		request.headers.get('x-real-ip') ??
+		'';
+	createUserSession(user.id, authSessionId, userAgent, ip).catch((e) =>
+		log.warn('api/auth/register', 'createUserSession failed (non-fatal)', { err: String(e) })
+	);
+
+	const token = createAuthToken(user.id, user.username, user.role ?? 'user', authSessionId);
+
+	cookies.set(AUTH_COOKIE, token, {
+		path: '/',
+		httpOnly: true,
+		sameSite: 'lax',
+		maxAge: ONE_YEAR
+	});
+
+	return json({
+		token,
+		user: { id: user.id, username: user.username, role: user.role ?? 'user' }
+	});
+};