chore(release): clean up repo for v0.0.1 release

Excluded from release bundle:
- CONTEXT.md, CHANGELOG.md (agent/project working notes)
- client-app/ (React Native messenger — tracked separately)
- contracts/hello_go/ (unused standalone example)

Kept contracts/counter/ and contracts/name_registry/ as vm-test fixtures
(referenced by vm/vm_test.go; NOT production contracts).

Docs refactor:
- docs/README.md — new top-level index with cross-references
- docs/quickstart.md — rewrite around single-node as primary path
- docs/node/README.md — full rewrite, all CLI flags, schema table
- docs/api/README.md — add /api/well-known-version, /api/update-check
- docs/contracts/README.md — split native (Go) vs WASM (user-deployable)
- docs/update-system.md — new, full 5-layer update system design
- README.md — link into docs/, drop CHANGELOG/client-app references

Build-time version system (inherited from earlier commits this branch):
- node --version / client --version with ldflags-injected metadata
- /api/well-known-version with {build, protocol_version, features[]}
- Peer-version gossip on dchain/version/v1
- /api/update-check against Gitea release API
- deploy/single/update.sh with semver guard + 15-min systemd jitter

client-app/README.md

@@ -1,93 +0,0 @@
-# DChain Messenger — React Native Client
-
-E2E-encrypted mobile/desktop messenger built on the DChain blockchain stack.
-
-**Stack:** React Native · Expo · NativeWind (Tailwind) · TweetNaCl · Zustand
-
-## Quick Start
-
-```bash
-cd client-app
-npm install
-npx expo start          # opens Expo Dev Tools
-# Press 'i' for iOS simulator, 'a' for Android, 'w' for web
-```
-
-## Requirements
-
-- Node.js 18+
-- [Expo Go](https://expo.dev/client) on your phone (for Expo tunnel), or iOS/Android emulator
-- A running DChain node (see root README for `docker compose up --build -d`)
-
-## Project Structure
-
-```
-client-app/
-├── app/
-│   ├── _layout.tsx           # Root layout — loads keys, sets up nav
-│   ├── index.tsx             # Welcome / onboarding
-│   ├── (auth)/
-│   │   ├── create.tsx        # Generate new Ed25519 + X25519 keys
-│   │   ├── created.tsx       # Key created — export reminder
-│   │   └── import.tsx        # Import existing key.json
-│   └── (app)/
-│       ├── _layout.tsx       # Tab bar — Chats · Wallet · Settings
-│       ├── chats/
-│       │   ├── index.tsx     # Chat list with contacts
-│       │   └── [id].tsx      # Individual chat with E2E encryption
-│       ├── requests.tsx      # Incoming contact requests
-│       ├── new-contact.tsx   # Add contact by @username or address
-│       ├── wallet.tsx        # Balance + TX history + send
-│       └── settings.tsx      # Node URL, key export, profile
-├── components/ui/            # shadcn-style components (Button, Card, Input…)
-├── hooks/
-│   ├── useMessages.ts        # Poll relay inbox, decrypt messages
-│   ├── useBalance.ts         # Poll token balance
-│   └── useContacts.ts        # Load contacts + poll contact requests
-└── lib/
-    ├── api.ts                # REST client for all DChain endpoints
-    ├── crypto.ts             # NaCl box encrypt/decrypt, Ed25519 sign
-    ├── storage.ts            # SecureStore (keys) + AsyncStorage (data)
-    ├── store.ts              # Zustand global state
-    ├── types.ts              # TypeScript interfaces
-    └── utils.ts              # cn(), formatAmount(), relativeTime()
-```
-
-## Cryptography
-
-| Operation | Algorithm | Library |
-|-----------|-----------|---------|
-| Transaction signing | Ed25519 | TweetNaCl `sign` |
-| Key exchange | X25519 (Curve25519) | TweetNaCl `box` |
-| Message encryption | NaCl box (XSalsa20-Poly1305) | TweetNaCl `box` |
-| Key storage | Device secure enclave | expo-secure-store |
-
-Messages are encrypted as:
-```
-Envelope {
-  sender_pub:    <X25519 hex>   // sender's public key
-  recipient_pub: <X25519 hex>   // recipient's public key
-  nonce:         <24-byte hex>  // random per message
-  ciphertext:    <hex>          // NaCl box(plaintext, nonce, sender_priv, recipient_pub)
-}
-```
-
-## Connect to your node
-
-1. Start the DChain node: `docker compose up --build -d`
-2. Open the app → Settings → Node URL → `http://YOUR_IP:8081`
-3. If using Expo Go on physical device: your PC and phone must be on the same network, or use `npx expo start --tunnel`
-
-## Key File Format
-
-The `key.json` exported/imported by the app:
-```json
-{
-  "pub_key":     "26018d40...",   // Ed25519 public key (64 hex chars)
-  "priv_key":    "...",           // Ed25519 private key (128 hex chars)
-  "x25519_pub":  "...",           // X25519 public key (64 hex chars)
-  "x25519_priv": "..."            // X25519 private key (64 hex chars)
-}
-```
-
-This is the same format as the Go node's `--key` flag.