feat(client): Twitter-style social feed UI (Phase C of v2.0.0)

Ships the client side of the v2.0.0 feed feature. Folds client-app/
into the monorepo (was previously .gitignored as "tracked separately"
but no separate repo ever existed — for v2.0.0 the client is
first-class).

Feed screens

  app/(app)/feed.tsx — Feed tab
    - Three-way tab strip: Подписки / Для вас / В тренде backed by
      /feed/timeline, /feed/foryou, /feed/trending respectively
    - Default landing tab is "Для вас" — surfaces discovery without
      requiring the user to follow anyone first
    - FlatList with pull-to-refresh + viewability-driven view counter
      bump (posts visible ≥ 60% for ≥ 1s trigger POST /feed/post/…/view)
    - Floating blue compose button → /compose
    - Per-post liked_by_me fetched in batches of 6 after list load

  app/(app)/compose.tsx — post composer modal
    - Fullscreen, Twitter-like header (✕ left, Опубликовать right)
    - Auto-focused multiline TextInput, 4000 char cap
    - Hashtag preview chips that auto-update as you type
    - expo-image-picker + expo-image-manipulator pipeline: resize to
      1080px max-dim, JPEG Q=50 (client-side first-pass compression
      before the mandatory server-side scrub)
    - Live fee estimate + balance guard with a confirmation modal
      ("Опубликовать пост? Цена: 0.00X T · Размер: N KB")
    - Exif: false passed to ImagePicker as an extra privacy layer

  app/(app)/feed/[id].tsx — post detail
    - Full PostCard rendering + detailed info panel (views, likes,
      size, fee, hosting relay, hashtags as tappable chips)
    - Triggers bumpView on mount
    - 410 (on-chain soft-delete) routes back to the feed

  app/(app)/feed/tag/[tag].tsx — hashtag feed

  app/(app)/profile/[address].tsx — rebuilt
    - Twitter-ish profile: avatar, name, address short-form, post count
    - Posts | Инфо tab strip
    - Follow / Unfollow button for non-self profiles (optimistic UI)
    - Edit button on self profile → settings
    - Secondary actions (chat, copy address) when viewing a known contact

Supporting library

  lib/feed.ts — HTTP wrappers + tx builders for every /feed/* endpoint:
    - publishPost (POST /feed/publish, signed)
    - publishAndCommit (publish → on-chain CREATE_POST)
    - fetchPost / fetchStats / bumpView
    - fetchAuthorPosts / fetchTimeline / fetchForYou / fetchTrending /
      fetchHashtag
    - buildCreatePostTx / buildDeletePostTx
    - buildFollowTx / buildUnfollowTx
    - buildLikePostTx / buildUnlikePostTx
    - likePost / unlikePost / followUser / unfollowUser / deletePost
      (high-level helpers that bundle build + submitTx)
    - formatFee, formatRelativeTime, formatCount — Twitter-like display
      helpers

  components/feed/PostCard.tsx — core card component
    - Memoised for performance (N-row re-render on every like elsewhere
      would cost a lot otherwise)
    - Optimistic like toggle with heart-bounce spring animation
    - Hashtag highlighting in body text (tappable → hashtag feed)
    - Long-press context menu (Delete, owner-only)
    - Views / likes / share-link / reply icons in footer row

Navigation cleanup

  - NavBar: removed the SOON pill on the Feed tab (it's shipped now)
  - (app)/_layout: hide NavBar on /compose and /feed/* sub-routes
  - AnimatedSlot: treat /feed/<id>, /feed/tag/<t>, /compose as
    sub-routes so back-swipe-right closes them

Channel removal (client side)

  - lib/types.ts: ContactKind stripped to 'direct' | 'group'; legacy
    'channel' flag removed. `kind` field kept for backward compat with
    existing AsyncStorage records.
  - lib/devSeed.ts: dropped the 5 channel seed contacts.
  - components/ChatTile.tsx: removed channel kindIcon branch.

Dependencies

  - expo-image-manipulator added for client-side image compression.
  - expo-file-system/legacy used for readAsStringAsync (SDK 54 moved
    that API to the legacy sub-path; the new streaming API isn't yet
    stable).

Type check

  - npx tsc --noEmit — clean, 0 errors.

Next (not in this commit)

  - Direct attachment-bytes endpoint on the server so post-detail can
    actually render the image (currently shows placeholder with URL)
  - Cross-relay body fetch via /api/relays + hosting_relay pubkey
  - Mentions (@username) with notifications
  - Full-text search

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

client-app/components/ChatTile.tsx

@@ -0,0 +1,174 @@
+/**
+ * ChatTile — одна строка в списке чатов на главной (Messages screen).
+ *
+ * Layout:
+ *   [avatar 44] [name (+verified) (+kind-icon)] [time]
+ *               [last-msg preview]               [unread pill]
+ *
+ * Kind-icon — мегафон для channel, 👥 для group, ничего для direct.
+ * Verified checkmark — если у контакта есть @username.
+ * Online-dot на аватарке — только для direct-чатов с x25519 ключом.
+ */
+import React from 'react';
+import { View, Text, Pressable } from 'react-native';
+import { Ionicons } from '@expo/vector-icons';
+
+import type { Contact, Message } from '@/lib/types';
+import { Avatar } from '@/components/Avatar';
+import { formatWhen } from '@/lib/dates';
+import { useStore } from '@/lib/store';
+
+function previewText(s: string, max = 50): string {
+  return s.length <= max ? s : s.slice(0, max).trimEnd() + '…';
+}
+
+/**
+ * Текстовое превью последнего сообщения. Если у сообщения нет текста
+ * (только вложение) — возвращаем маркер с иконкой названием типа:
+ *   "🖼 Photo"  / "🎬 Video" / "🎙 Voice" / "📎 File"
+ * Если текст есть — он используется; если есть и то и другое, префикс
+ * добавляется перед текстом.
+ */
+function lastPreview(m: Message): string {
+  const emojiByKind = {
+    image: '🖼', video: '🎬', voice: '🎙', file: '📎',
+  } as const;
+  const labelByKind = {
+    image: 'Photo', video: 'Video', voice: 'Voice message', file: 'File',
+  } as const;
+  const text = m.text.trim();
+  if (m.attachment) {
+    const prefix = `${emojiByKind[m.attachment.kind]} ${labelByKind[m.attachment.kind]}`;
+    return text ? `${prefix}  ${previewText(text, 40)}` : prefix;
+  }
+  return previewText(text);
+}
+
+function shortAddr(a: string, n = 5): string {
+  if (!a) return '—';
+  return a.length <= n * 2 + 1 ? a : `${a.slice(0, n)}…${a.slice(-n)}`;
+}
+
+function displayName(c: Contact): string {
+  return c.username ? `@${c.username}` : c.alias ?? shortAddr(c.address);
+}
+
+export interface ChatTileProps {
+  contact:     Contact;
+  lastMessage: Message | null;
+  onPress:     () => void;
+}
+
+export function ChatTile({ contact: c, lastMessage, onPress }: ChatTileProps) {
+  const name = displayName(c);
+  const last = lastMessage;
+
+  // Визуальный маркер типа чата.
+  const kindIcon: React.ComponentProps<typeof Ionicons>['name'] | null =
+    c.kind === 'group' ? 'people' : null;
+
+  // Unread берётся из runtime-store'а (инкрементится в useGlobalInbox,
+  // обнуляется при открытии чата). Fallback на c.unread для legacy seed.
+  const storeUnread = useStore(s => s.unreadByContact[c.address] ?? 0);
+  const unreadCount = storeUnread || (c.unread ?? 0);
+  const unread = unreadCount > 0 ? unreadCount : null;
+
+  return (
+    <Pressable
+      onPress={onPress}
+      style={({ pressed }) => ({
+        backgroundColor: pressed ? '#0a0a0a' : 'transparent',
+      })}
+    >
+      <View
+        style={{
+          flexDirection: 'row',
+          alignItems: 'flex-start',
+          paddingHorizontal: 14,
+          paddingVertical: 12,
+        }}
+      >
+        <Avatar
+          name={name}
+          address={c.address}
+          size={44}
+          dotColor={c.x25519Pub && (!c.kind || c.kind === 'direct') ? '#3ba55d' : undefined}
+        />
+
+        <View style={{ flex: 1, marginLeft: 12, minWidth: 0 }}>
+          {/* Первая строка: [kind-icon] name [verified] ··· time */}
+          <View style={{ flexDirection: 'row', alignItems: 'center' }}>
+            {kindIcon && (
+              <Ionicons
+                name={kindIcon}
+                size={12}
+                color="#8b8b8b"
+                style={{ marginRight: 5 }}
+              />
+            )}
+            <Text
+              numberOfLines={1}
+              style={{ color: '#ffffff', fontWeight: '700', fontSize: 15, flex: 1 }}
+            >
+              {name}
+            </Text>
+            {c.username && (
+              <Ionicons
+                name="checkmark-circle"
+                size={14}
+                color="#1d9bf0"
+                style={{ marginLeft: 4, marginRight: 2 }}
+              />
+            )}
+            {last && (
+              <Text style={{ color: '#8b8b8b', fontSize: 12, marginLeft: 6 }}>
+                {formatWhen(last.timestamp)}
+              </Text>
+            )}
+          </View>
+
+          {/* Вторая строка: [✓✓ mine-seen] preview ··· [unread] */}
+          <View style={{ flexDirection: 'row', alignItems: 'center', marginTop: 3 }}>
+            {last?.mine && (
+              <Ionicons
+                name="checkmark-done-outline"
+                size={13}
+                color="#8b8b8b"
+                style={{ marginRight: 4 }}
+              />
+            )}
+            <Text
+              numberOfLines={1}
+              style={{ color: '#8b8b8b', fontSize: 13, flex: 1 }}
+            >
+              {last
+                ? lastPreview(last)
+                : c.x25519Pub
+                  ? 'Tap to start encrypted chat'
+                  : 'Waiting for identity…'}
+            </Text>
+
+            {unread !== null && (
+              <View
+                style={{
+                  marginLeft: 8,
+                  minWidth: 18,
+                  height: 18,
+                  paddingHorizontal: 5,
+                  borderRadius: 9,
+                  backgroundColor: '#1d9bf0',
+                  alignItems: 'center',
+                  justifyContent: 'center',
+                }}
+              >
+                <Text style={{ color: '#ffffff', fontSize: 11, fontWeight: '700' }}>
+                  {unread > 99 ? '99+' : unread}
+                </Text>
+              </View>
+            )}
+          </View>
+        </View>
+      </View>
+    </Pressable>
+  );
+}