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

ios/.gitignore

@@ -0,0 +1,14 @@
+# Xcode build artifacts — regenerate with: xcodegen generate --spec project.yml
+xcuserdata/
+*.xcuserstate
+*.xcworkspace/xcuserdata/
+DerivedData/
+build/
+
+# Swift Package Manager — resolved by Xcode on first open
+LibNovel.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/
+.build/
+# Package.resolved is committed so SPM builds are reproducible
+
+# OS
+.DS_Store