```
chatapp/
├── .git/                      # Git version control
├── .vscode/                   # VSCode workspace settings
│   └── extensions.json        # Recommended extensions
├── Client/                    # Frontend application (React + Capacitor)
├── Server/                    # Backend relay server (Go)
├── Notes/                     # Development notes and resources
├── docs/                      # Documentation (this folder)
├── .gitignore                 # Git ignore rules (root level)
└── readme.md                  # Main project README
```

```
Client/
├── .browserslistrc            # Browser compatibility targets
├── .gitignore                 # Client-specific git ignores
├── android/                   # Android platform (Capacitor)
│   ├── app/
│   │   ├── build.gradle       # Android build configuration
│   │   ├── google-services.json # Firebase/Google services
│   │   ├── proguard-rules.pro # Code obfuscation rules
│   │   └── src/               # Android native code
│   ├── gradle/                # Gradle wrapper
│   ├── build.gradle           # Project-level Gradle config
│   └── settings.gradle        # Gradle settings
├── assets/                    # Static assets (images, fonts)
├── capacitor.config.ts        # Capacitor configuration
├── cypress/                   # End-to-end tests
│   ├── e2e/                   # Test specs
│   ├── fixtures/              # Test data
│   └── support/               # Test helpers
├── cypress.config.ts          # Cypress configuration
├── dist/                      # Build output (generated, not in git)
├── electron/                  # Electron platform
│   ├── dist/                  # Electron build output
│   ├── preload.js             # Electron preload script
│   ├── main.js                # Electron main process
│   └── package.json           # Electron dependencies
├── eslint.config.js           # ESLint linting rules
├── icons/                     # App icons (various sizes)
├── index.html                 # HTML entry point
├── ionic.config.json          # Ionic CLI configuration
├── node_modules/              # NPM dependencies (generated)
├── package.json               # NPM package manifest
├── package-lock.json          # NPM dependency lock file
├── public/                    # Static public assets
│   ├── favicon.ico            # Browser favicon
│   └── manifest.json          # PWA manifest
├── readme.md                  # Client README
├── src/                       # Source code (React app)
├── sync.cjs                   # Capacitor sync script
├── tsconfig.json              # TypeScript configuration
├── tsconfig.node.json         # TypeScript config for Node scripts
└── vite.config.ts             # Vite bundler configuration
```

```
src/
├── App.tsx                    # Root React component & routing
├── main.tsx                   # React entry point
├── vite-env.d.ts              # Vite type definitions
├── assets/                    # Bundled assets (SVGs, images)
├── components/                # Shared React components
│   ├── EmojiPicker.tsx        # Emoji selection popover
│   ├── GifPicker.tsx          # Tenor GIF search & selection
│   ├── UserAvatar.tsx         # User avatar with presence indicator
│   └── ui/                    # Low-level UI primitives
│       ├── Avatar.tsx         # Base avatar element
│       ├── Button.tsx         # Button variants
│       ├── Card.tsx           # Card layout container
│       └── IconButton.tsx     # Icon-only button
├── hooks/                     # Shared custom React hooks
│   └── useRecentEmojis.ts     # Persists recently used emojis
├── pages/                     # Page-level components
│   ├── Home/                  # Main chat page
│   │   ├── Home.tsx           # Root layout: sidebar + chat window
│   │   ├── Home.styles.ts     # Styled-component definitions
│   │   ├── types.ts           # Shared TypeScript interfaces (ChatMessage, etc.)
│   │   ├── components/        # Home-specific sub-components
│   │   └── hooks/             # Home-specific hooks (chat logic, calls, etc.)
│   ├── SecureChat/            # Secure Vault page
│   │   ├── SecureChatWindow.tsx  # Vault UI (passwords, files, notes)
│   │   ├── SecureChatWindow.css  # Vault styles
│   │   ├── SavePasswordModal.tsx # Password save dialog
│   │   └── hooks/             # Vault-specific hooks
│   ├── LoadingScreen.tsx      # Splash/loading screen
│   └── Login.styles.ts        # Login page styles
├── services/                  # Business logic (organized by domain)
│   ├── ai/
│   │   └── qwenLocal.service.ts   # On-device Qwen LLM inference (WASM + Native)
│   ├── auth/
│   │   ├── AccountService.ts      # Account lifecycle (add, switch, remove)
│   │   └── AuthService.ts         # Google OAuth token management
│   ├── core/
│   │   ├── ChatClient.ts          # Singleton orchestrator: WS, encryption, event dispatch
│   │   ├── LoggerService.ts       # Structured logging service
│   │   ├── SocketManager.ts       # Raw WebSocket connection & auto-reconnect
│   │   ├── WorkerManager.ts       # Crypto Web Worker pool with priority queue
│   │   ├── interfaces.ts          # Core TypeScript interfaces (IChatClient)
│   │   └── protocolLimits.ts      # Frame size / rate-limit constants
│   ├── media/
│   │   ├── CallService.ts         # WebRTC voice & video call management
│   │   ├── CompressionService.ts  # Image/file compression before upload
│   │   ├── FileTransferService.ts # Chunked encrypted file send/receive
│   │   └── VideoTranscoder.ts     # Video transcoding helper for Android
│   ├── messaging/
│   │   ├── MessageService.ts      # Message send/receive, edit, delete, reactions, MANIFEST sync
│   │   └── SessionService.ts      # Session lifecycle, key derivation, presence, friend requests
│   ├── mfa/
│   │   ├── mfa.service.ts              # TOTP generation & verification
│   │   ├── platform-launch.service.ts  # Platform-specific deep link launcher
│   │   ├── qr.service.ts               # QR code generation for MFA setup
│   │   └── secure-storage.adapter.ts   # MFA secret storage adapter
│   └── storage/
│       ├── AvatarCacheService.ts  # In-memory LRU cache for peer avatar data URIs
│       ├── BackupService.ts       # Encrypted ZIP backup & restore
│       ├── PlatformStorage.ts     # Platform-aware storage abstraction
│       ├── SafeStorage.ts         # Secure key storage (Keychain/Keystore)
│       ├── StorageService.ts      # File storage (vault media, avatars, profile images)
│       ├── StorageUtils.ts        # Storage path/key constants
│       ├── VaultCrypto.ts         # Vault-specific AES-GCM encryption helpers
│       └── sqliteService.ts       # SQLite database wrapper & schema
├── theme/                     # CSS design tokens
│   └── variables.css          # Color schemes, spacing, typography
├── types/                     # Global TypeScript type declarations
├── utils/                     # Pure utility functions
│   ├── crypto.ts              # Encryption/decryption helpers (ECDH, AES-GCM)
│   ├── imageUtils.ts          # Image resizing, thumbnail generation
│   ├── MessageQueue.ts        # Offline message queue implementation
│   ├── secureStorage.ts       # Low-level Capacitor SecureStorage wrapper
│   └── trustedDomains.ts      # Allowlist for link previews
└── workers/                   # Web Workers (off-main-thread processing)
    ├── crypto.worker.ts       # Parallel encryption/decryption worker
```

```
Server/
├── main.go              # Entry point – bootstraps server, DB, and HTTP server
├── server.go            # WebSocket upgrade, connection registry, hub
├── handlers.go          # Frame handler dispatch for all message types
├── auth.go              # Session token generation/validation & Google OAuth verify
├── db.go                # SQLite schema init & query helpers
├── fcm.go               # Firebase Cloud Messaging (push notifications)
├── types.go             # Shared Go structs (Frame, Client, Session, etc.)
├── utils.go             # Utility helpers (ID generation, hashing, etc.)
├── go.mod               # Go module definition
├── go.sum               # Go dependency checksums
├── .env                 # Server environment variables (KEEP SECRET!)
├── .example.env         # Environment variable template
├── website/             # Static landing page assets
└── readme.md            # Server README
```

```
docs/
├── OVERVIEW.md                  # Application overview & target users
├── ARCHITECTURE.md              # System architecture & component diagram
├── USER_FLOWS.md                # User journey flows with flowcharts
├── AUTHENTICATION.md            # Auth system, OAuth, session management
├── FEATURES.md                  # Feature-by-feature breakdown
├── WEBSOCKET_PROTOCOL.md        # Protocol specification & frame types
├── DATABASE.md                  # Database schema, tables, ER diagrams
├── SECURITY.md                  # Security protocols & threat model
├── DEPLOYMENT.md                # Deployment guide (Android, Electron, server)
├── SETUP.md                     # Build & run instructions
├── FOLDER_STRUCTURE.md          # This file
├── EXPERIMENTAL_VALIDATION.md   # Performance benchmarks & validation results
├── ACADEMIC_PROJECT_REPORT.md   # Full academic project report
└── images/                      # SVG/PNG diagrams referenced by docs
```