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/Avatar.tsx

@@ -0,0 +1,37 @@
+import React from 'react';
+import { View, Text } from 'react-native';
+import { cn } from '@/lib/utils';
+
+/** Deterministic color from a string */
+function colorFor(str: string): string {
+  const colors = [
+    'bg-blue-600', 'bg-purple-600', 'bg-green-600',
+    'bg-pink-600',  'bg-orange-600', 'bg-teal-600',
+    'bg-red-600',   'bg-indigo-600', 'bg-cyan-600',
+  ];
+  let h = 0;
+  for (let i = 0; i < str.length; i++) h = (h * 31 + str.charCodeAt(i)) >>> 0;
+  return colors[h % colors.length];
+}
+
+interface AvatarProps {
+  name?:      string;
+  size?:      'sm' | 'md' | 'lg';
+  className?: string;
+}
+
+const sizeMap = {
+  sm: { outer: 'w-8 h-8',   text: 'text-sm'  },
+  md: { outer: 'w-10 h-10', text: 'text-base' },
+  lg: { outer: 'w-14 h-14', text: 'text-xl'  },
+};
+
+export function Avatar({ name = '?', size = 'md', className }: AvatarProps) {
+  const initials = name.slice(0, 2).toUpperCase();
+  const { outer, text } = sizeMap[size];
+  return (
+    <View className={cn(outer, colorFor(name), 'rounded-full items-center justify-center', className)}>
+      <Text className={cn(text, 'text-white font-bold')}>{initials}</Text>
+    </View>
+  );
+}

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>
+  );
+}

client-app/components/ui/Button.tsx

@@ -0,0 +1,76 @@
+import React from 'react';
+import { Pressable, Text, ActivityIndicator } from 'react-native';
+import { cva, type VariantProps } from 'class-variance-authority';
+import { cn } from '@/lib/utils';
+
+const buttonVariants = cva(
+  'flex-row items-center justify-center rounded-xl px-5 py-3 active:opacity-80',
+  {
+    variants: {
+      variant: {
+        default:     'bg-primary',
+        secondary:   'bg-surfaceHigh border border-border',
+        destructive: 'bg-destructive',
+        ghost:       'bg-transparent',
+        outline:     'bg-transparent border border-primary',
+      },
+      size: {
+        sm:   'px-3 py-2',
+        md:   'px-5 py-3',
+        lg:   'px-6 py-4',
+        icon: 'p-2',
+      },
+    },
+    defaultVariants: {
+      variant: 'default',
+      size:    'md',
+    },
+  },
+);
+
+const textVariants = cva('font-semibold text-center', {
+  variants: {
+    variant: {
+      default:     'text-white',
+      secondary:   'text-white',
+      destructive: 'text-white',
+      ghost:       'text-primary',
+      outline:     'text-primary',
+    },
+    size: {
+      sm:   'text-sm',
+      md:   'text-base',
+      lg:   'text-lg',
+      icon: 'text-base',
+    },
+  },
+  defaultVariants: {
+    variant: 'default',
+    size:    'md',
+  },
+});
+
+interface ButtonProps extends VariantProps<typeof buttonVariants> {
+  onPress?:   () => void;
+  disabled?:  boolean;
+  loading?:   boolean;
+  children:   React.ReactNode;
+  className?: string;
+}
+
+export function Button({
+  variant, size, onPress, disabled, loading, children, className,
+}: ButtonProps) {
+  return (
+    <Pressable
+      onPress={onPress}
+      disabled={disabled || loading}
+      className={cn(buttonVariants({ variant, size }), disabled && 'opacity-50', className)}
+    >
+      {loading
+        ? <ActivityIndicator color="#fff" size="small" />
+        : <Text className={textVariants({ variant, size })}>{children}</Text>
+      }
+    </Pressable>
+  );
+}

client-app/components/ui/Card.tsx

@@ -0,0 +1,16 @@
+import React from 'react';
+import { View } from 'react-native';
+import { cn } from '@/lib/utils';
+
+interface CardProps {
+  children:   React.ReactNode;
+  className?: string;
+}
+
+export function Card({ children, className }: CardProps) {
+  return (
+    <View className={cn('bg-surface border border-border rounded-2xl p-4', className)}>
+      {children}
+    </View>
+  );
+}

client-app/components/ui/Input.tsx

@@ -0,0 +1,34 @@
+import React, { forwardRef } from 'react';
+import { TextInput, View, Text, type TextInputProps } from 'react-native';
+import { cn } from '@/lib/utils';
+
+interface InputProps extends TextInputProps {
+  label?:     string;
+  error?:     string;
+  className?: string;
+}
+
+export const Input = forwardRef<TextInput, InputProps>(
+  ({ label, error, className, ...props }, ref) => (
+    <View className="w-full gap-1">
+      {label && (
+        <Text className="text-muted text-sm font-medium mb-1">{label}</Text>
+      )}
+      <TextInput
+        ref={ref}
+        placeholderTextColor="#8b949e"
+        className={cn(
+          'bg-surfaceHigh border border-border rounded-xl px-4 py-3 text-white text-base',
+          error && 'border-destructive',
+          className,
+        )}
+        {...props}
+      />
+      {error && (
+        <Text className="text-destructive text-xs mt-1">{error}</Text>
+      )}
+    </View>
+  ),
+);
+
+Input.displayName = 'Input';

client-app/components/ui/Separator.tsx

@@ -0,0 +1,7 @@
+import React from 'react';
+import { View } from 'react-native';
+import { cn } from '@/lib/utils';
+
+export function Separator({ className }: { className?: string }) {
+  return <View className={cn('h-px bg-border my-2', className)} />;
+}

client-app/components/ui/index.ts

@@ -0,0 +1,6 @@
+export { Button }    from './Button';
+export { Card }      from './Card';
+export { Input }     from './Input';
+export { Avatar }    from './Avatar';
+export { Badge }     from './Badge';
+export { Separator } from './Separator';