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/app/(app)/chats/index.tsx

@@ -0,0 +1,337 @@
+/**
+ * Chat list — DChain messenger.
+ * Safe-area aware, Ionicons, polished empty states, responsive press feedback.
+ */
+
+import React, { useCallback, useMemo, useEffect, useState } from 'react';
+import { View, Text, FlatList, Pressable, TouchableOpacity } from 'react-native';
+import { router } from 'expo-router';
+import { Ionicons } from '@expo/vector-icons';
+import { useSafeAreaInsets } from 'react-native-safe-area-context';
+import { useStore } from '@/lib/store';
+import { getWSClient } from '@/lib/ws';
+import { Avatar } from '@/components/ui/Avatar';
+import { formatTime, formatAmount } from '@/lib/utils';
+import type { Contact } from '@/lib/types';
+
+const MIN_FEE = 5000;
+
+// ─── Design tokens ────────────────────────────────────────────────────────────
+const C = {
+  bg:       '#0b1220',
+  surface:  '#111a2b',
+  surface2: '#162035',
+  surface3: '#1a2640',
+  line:     '#1c2840',
+  text:     '#e6edf9',
+  muted:    '#98a7c2',
+  accent:   '#7db5ff',
+  ok:       '#41c98a',
+  warn:     '#f0b35a',
+  err:      '#ff7a87',
+} as const;
+
+// ─── Helpers ──────────────────────────────────────────────────────────────────
+
+/** Truncate a message preview without breaking words too awkwardly. */
+function previewText(s: string, max = 60): string {
+  if (s.length <= max) return s;
+  return s.slice(0, max).trimEnd() + '…';
+}
+
+/** Short address helper matching the rest of the app. */
+function shortAddr(a: string, n = 6): string {
+  if (!a) return '—';
+  return a.length <= n * 2 + 1 ? a : `${a.slice(0, n)}…${a.slice(-n)}`;
+}
+
+export default function ChatsScreen() {
+  const contacts = useStore(s => s.contacts);
+  const messages = useStore(s => s.messages);
+  const requests = useStore(s => s.requests);
+  const balance  = useStore(s => s.balance);
+  const keyFile  = useStore(s => s.keyFile);
+  const insets   = useSafeAreaInsets();
+
+  // Real-time transport indicator (green dot when WS is live, yellow when
+  // using HTTP polling fallback).
+  const [wsLive, setWsLive] = useState(false);
+  useEffect(() => {
+    const ws = getWSClient();
+    setWsLive(ws.isConnected());
+    return ws.onConnectionChange(ok => setWsLive(ok));
+  }, []);
+
+  const hasBalance = balance >= MIN_FEE;
+
+  const displayName = (c: Contact) =>
+    c.username ? `@${c.username}` : c.alias ?? shortAddr(c.address, 5);
+
+  const lastMsg = (c: Contact) => {
+    const msgs = messages[c.address];
+    return msgs?.length ? msgs[msgs.length - 1] : null;
+  };
+
+  // Sort contacts: most recent activity first.
+  const sortedContacts = useMemo(() => {
+    const withTime = contacts.map(c => {
+      const last = lastMsg(c);
+      return {
+        contact: c,
+        sortKey: last ? last.timestamp : (c.addedAt / 1000),
+      };
+    });
+    return withTime
+      .sort((a, b) => b.sortKey - a.sortKey)
+      .map(x => x.contact);
+  }, [contacts, messages]);
+
+  const renderItem = useCallback(({ item: c, index }: { item: Contact; index: number }) => {
+    const last     = lastMsg(c);
+    const name     = displayName(c);
+    const hasKey   = !!c.x25519Pub;
+
+    return (
+      <Pressable
+        onPress={() => router.push(`/(app)/chats/${c.address}`)}
+        android_ripple={{ color: C.surface2 }}
+        style={({ pressed }) => ({
+          flexDirection: 'row', alignItems: 'center',
+          paddingHorizontal: 14, paddingVertical: 12,
+          borderTopWidth: index === 0 ? 0 : 1, borderTopColor: C.line,
+          backgroundColor: pressed ? C.surface2 : 'transparent',
+        })}
+      >
+        {/* Avatar with E2E status pip */}
+        <View style={{ position: 'relative', marginRight: 12 }}>
+          <Avatar name={name} size="md" />
+          {hasKey && (
+            <View style={{
+              position: 'absolute', right: -2, bottom: -2,
+              width: 14, height: 14, borderRadius: 7,
+              backgroundColor: C.ok,
+              borderWidth: 2, borderColor: C.bg,
+              alignItems: 'center', justifyContent: 'center',
+            }}>
+              <Ionicons name="lock-closed" size={7} color="#0b1220" />
+            </View>
+          )}
+        </View>
+
+        {/* Text column */}
+        <View style={{ flex: 1, minWidth: 0 }}>
+          <View style={{ flexDirection: 'row', alignItems: 'center' }}>
+            <Text
+              style={{ color: C.text, fontWeight: '600', fontSize: 15, flex: 1 }}
+              numberOfLines={1}
+            >
+              {name}
+            </Text>
+            {last && (
+              <Text style={{ color: C.muted, fontSize: 11, marginLeft: 8 }}>
+                {formatTime(last.timestamp)}
+              </Text>
+            )}
+          </View>
+          <View style={{ flexDirection: 'row', alignItems: 'center', marginTop: 2 }}>
+            {last?.mine && (
+              <Ionicons
+                name="checkmark-done-outline"
+                size={13}
+                color={C.muted}
+                style={{ marginRight: 4 }}
+              />
+            )}
+            <Text
+              style={{ color: C.muted, fontSize: 13, flex: 1 }}
+              numberOfLines={1}
+            >
+              {last ? previewText(last.text) : (hasKey ? 'Напишите первое сообщение' : 'Ожидание публикации ключа…')}
+            </Text>
+          </View>
+        </View>
+      </Pressable>
+    );
+  }, [messages, lastMsg]);
+
+  return (
+    <View style={{ flex: 1, backgroundColor: C.bg }}>
+
+      {/* ── Header ── */}
+      <View style={{
+        flexDirection: 'row', alignItems: 'center', justifyContent: 'space-between',
+        paddingHorizontal: 16,
+        paddingTop: insets.top + 10,
+        paddingBottom: 14,
+        borderBottomWidth: 1, borderBottomColor: C.line,
+      }}>
+        <View>
+          <Text style={{ color: C.text, fontSize: 22, fontWeight: '700', letterSpacing: -0.3 }}>
+            Сообщения
+          </Text>
+          {contacts.length > 0 && (
+            <View style={{ flexDirection: 'row', alignItems: 'center', gap: 5, marginTop: 2 }}>
+              <Text style={{ color: C.muted, fontSize: 12 }}>
+                {contacts.length} {contacts.length === 1 ? 'контакт' : contacts.length < 5 ? 'контакта' : 'контактов'}
+                {' · '}
+                <Text style={{ color: C.ok }}>E2E</Text>
+                {'  ·  '}
+              </Text>
+              <View style={{
+                width: 6, height: 6, borderRadius: 3,
+                backgroundColor: wsLive ? C.ok : C.warn,
+              }} />
+              <Text style={{ color: wsLive ? C.ok : C.warn, fontSize: 11 }}>
+                {wsLive ? 'live' : 'polling'}
+              </Text>
+            </View>
+          )}
+        </View>
+
+        <View style={{ flexDirection: 'row', gap: 8, alignItems: 'center' }}>
+          {/* Incoming requests chip */}
+          {requests.length > 0 && (
+            <TouchableOpacity
+              onPress={() => router.push('/(app)/requests')}
+              activeOpacity={0.7}
+              style={{
+                flexDirection: 'row', alignItems: 'center', gap: 6,
+                backgroundColor: 'rgba(125,181,255,0.14)', borderRadius: 999,
+                paddingHorizontal: 12, paddingVertical: 7,
+                borderWidth: 1, borderColor: 'rgba(125,181,255,0.25)',
+              }}
+            >
+              <Ionicons name="mail-unread-outline" size={14} color={C.accent} />
+              <Text style={{ color: C.accent, fontSize: 12, fontWeight: '600' }}>
+                {requests.length}
+              </Text>
+            </TouchableOpacity>
+          )}
+
+          {/* Add contact button */}
+          <TouchableOpacity
+            onPress={() => hasBalance ? router.push('/(app)/new-contact') : router.push('/(app)/wallet')}
+            activeOpacity={0.7}
+            style={{
+              width: 38, height: 38, borderRadius: 19,
+              backgroundColor: hasBalance ? C.accent : C.surface2,
+              alignItems: 'center', justifyContent: 'center',
+            }}
+          >
+            <Ionicons
+              name={hasBalance ? 'add-outline' : 'lock-closed-outline'}
+              size={20}
+              color={hasBalance ? C.bg : C.muted}
+            />
+          </TouchableOpacity>
+        </View>
+      </View>
+
+      {/* ── No balance gate (no contacts) ── */}
+      {!hasBalance && contacts.length === 0 && (
+        <View style={{
+          margin: 16, padding: 18,
+          backgroundColor: 'rgba(125,181,255,0.07)',
+          borderRadius: 14,
+          borderWidth: 1, borderColor: 'rgba(125,181,255,0.15)',
+        }}>
+          <View style={{ flexDirection: 'row', alignItems: 'center', gap: 10, marginBottom: 8 }}>
+            <View style={{
+              width: 32, height: 32, borderRadius: 16,
+              backgroundColor: 'rgba(125,181,255,0.18)',
+              alignItems: 'center', justifyContent: 'center',
+            }}>
+              <Ionicons name="diamond-outline" size={16} color={C.accent} />
+            </View>
+            <Text style={{ color: C.text, fontWeight: '700', fontSize: 15 }}>
+              Пополните баланс
+            </Text>
+          </View>
+          <Text style={{ color: C.muted, fontSize: 13, lineHeight: 20, marginBottom: 14 }}>
+            Отправка запроса контакта стоит{' '}
+            <Text style={{ color: C.text, fontWeight: '600' }}>{formatAmount(MIN_FEE)}</Text>
+            {' '}— антиспам-сбор идёт напрямую получателю.
+          </Text>
+          <TouchableOpacity
+            onPress={() => router.push('/(app)/wallet')}
+            activeOpacity={0.7}
+            style={{
+              flexDirection: 'row', alignItems: 'center', justifyContent: 'center', gap: 8,
+              paddingVertical: 11, borderRadius: 10,
+              backgroundColor: C.accent,
+            }}
+          >
+            <Ionicons name="wallet-outline" size={16} color={C.bg} />
+            <Text style={{ color: C.bg, fontWeight: '700', fontSize: 13 }}>Перейти в кошелёк</Text>
+          </TouchableOpacity>
+        </View>
+      )}
+
+      {/* ── Low balance warning (has contacts) ── */}
+      {!hasBalance && contacts.length > 0 && (
+        <TouchableOpacity
+          onPress={() => router.push('/(app)/wallet')}
+          activeOpacity={0.7}
+          style={{
+            flexDirection: 'row', alignItems: 'center', gap: 10,
+            marginHorizontal: 16, marginTop: 12,
+            backgroundColor: 'rgba(255,122,135,0.08)',
+            borderRadius: 10, paddingHorizontal: 12, paddingVertical: 10,
+            borderWidth: 1, borderColor: 'rgba(255,122,135,0.18)',
+          }}
+        >
+          <Ionicons name="warning-outline" size={16} color={C.err} />
+          <Text style={{ color: C.err, fontSize: 13, flex: 1 }}>
+            Недостаточно токенов для добавления контакта
+          </Text>
+          <Ionicons name="chevron-forward" size={14} color={C.err} />
+        </TouchableOpacity>
+      )}
+
+      {/* ── Empty state (has balance, no contacts) ── */}
+      {contacts.length === 0 && hasBalance && (
+        <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center', paddingHorizontal: 32 }}>
+          <View style={{
+            width: 88, height: 88, borderRadius: 44,
+            backgroundColor: C.surface,
+            alignItems: 'center', justifyContent: 'center',
+            marginBottom: 18,
+          }}>
+            <Ionicons name="chatbubbles-outline" size={40} color={C.accent} />
+          </View>
+          <Text style={{ color: C.text, fontSize: 19, fontWeight: '700', textAlign: 'center', marginBottom: 8 }}>
+            Нет диалогов
+          </Text>
+          <Text style={{ color: C.muted, fontSize: 14, textAlign: 'center', lineHeight: 22, marginBottom: 20 }}>
+            Добавьте контакт по адресу или{' '}
+            <Text style={{ color: C.accent, fontWeight: '600' }}>@username</Text>
+            {' '}для начала зашифрованной переписки.
+          </Text>
+          <TouchableOpacity
+            onPress={() => router.push('/(app)/new-contact')}
+            activeOpacity={0.7}
+            style={{
+              flexDirection: 'row', alignItems: 'center', gap: 8,
+              paddingHorizontal: 22, paddingVertical: 12, borderRadius: 12,
+              backgroundColor: C.accent,
+            }}
+          >
+            <Ionicons name="person-add-outline" size={16} color={C.bg} />
+            <Text style={{ color: C.bg, fontWeight: '700', fontSize: 14 }}>Добавить контакт</Text>
+          </TouchableOpacity>
+        </View>
+      )}
+
+      {/* ── Chat list ── */}
+      {contacts.length > 0 && (
+        <FlatList
+          data={sortedContacts}
+          keyExtractor={c => c.address}
+          renderItem={renderItem}
+          contentContainerStyle={{ paddingBottom: 20 }}
+          showsVerticalScrollIndicator={false}
+        />
+      )}
+    </View>
+  );
+}