chore: initial commit for v0.0.1

DChain single-node blockchain + React Native messenger client.

Core:
- PBFT consensus with multi-sig validator admission + equivocation slashing
- BadgerDB + schema migration scaffold (CurrentSchemaVersion=0)
- libp2p gossipsub (tx/v1, blocks/v1, relay/v1, version/v1)
- Native Go contracts (username_registry) alongside WASM (wazero)
- WebSocket gateway with topic-based fanout + Ed25519-nonce auth
- Relay mailbox with NaCl envelope encryption (X25519 + Ed25519)
- Prometheus /metrics, per-IP rate limit, body-size cap

Deployment:
- Single-node compose (deploy/single/) with Caddy TLS + optional Prometheus
- 3-node dev compose (docker-compose.yml) with mocked internet topology
- 3-validator prod compose (deploy/prod/) for federation
- Auto-update from Gitea via /api/update-check + systemd timer
- Build-time version injection (ldflags → node --version)
- UI / Swagger toggle flags (DCHAIN_DISABLE_UI, DCHAIN_DISABLE_SWAGGER)

Client (client-app/):
- Expo / React Native / NativeWind
- E2E NaCl encryption, typing indicator, contact requests
- Auto-discovery of canonical contracts, chain_id aware, WS reconnect on node switch

Documentation:
- README.md, CHANGELOG.md, CONTEXT.md
- deploy/single/README.md with 6 operator scenarios
- deploy/UPDATE_STRATEGY.md with 4-layer forward-compat design
- docs/contracts/*.md per contract

client-app/components/ui/Badge.tsx

@@ -0,0 +1,24 @@
+import React from 'react';
+import { View, Text } from 'react-native';
+import { cn } from '@/lib/utils';
+
+interface BadgeProps {
+  label:      string | number;
+  variant?:   'default' | 'success' | 'destructive' | 'muted';
+  className?: string;
+}
+
+const variantMap = {
+  default:     'bg-primary',
+  success:     'bg-success',
+  destructive: 'bg-destructive',
+  muted:       'bg-surfaceHigh border border-border',
+};
+
+export function Badge({ label, variant = 'default', className }: BadgeProps) {
+  return (
+    <View className={cn('rounded-full px-2 py-0.5 items-center justify-center', variantMap[variant], className)}>
+      <Text className="text-white text-xs font-semibold">{label}</Text>
+    </View>
+  );
+}