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/chat/VideoCirclePlayer.tsx

@@ -0,0 +1,158 @@
+/**
+ * VideoCirclePlayer — telegram-style круглое видео-сообщение.
+ *
+ * Мигрировано с expo-av `<Video>` на expo-video `<VideoView>` +
+ * useVideoPlayer hook (expo-av deprecated в SDK 54).
+ *
+ * UI:
+ *   - Круглая thumbnail-рамка (Image превью первого кадра) с play-overlay
+ *   - Tap → полноэкранный Modal с VideoView в круглой рамке, auto-play + loop
+ *   - Duration badge снизу
+ */
+import React, { useState } from 'react';
+import { View, Text, Pressable, Modal, Image } from 'react-native';
+import { Ionicons } from '@expo/vector-icons';
+import { useVideoPlayer, VideoView } from 'expo-video';
+
+export interface VideoCirclePlayerProps {
+  uri:       string;
+  duration?: number;
+  size?:     number;
+}
+
+function formatClock(sec: number): string {
+  const m = Math.floor(sec / 60);
+  const s = Math.floor(sec % 60);
+  return `${m}:${String(s).padStart(2, '0')}`;
+}
+
+export function VideoCirclePlayer({ uri, duration, size = 220 }: VideoCirclePlayerProps) {
+  const [open, setOpen] = useState(false);
+  return (
+    <>
+      <Pressable
+        onPress={() => setOpen(true)}
+        style={{
+          width: size, height: size, borderRadius: size / 2,
+          overflow: 'hidden',
+          backgroundColor: '#0a0a0a',
+          marginBottom: 4,
+          alignItems: 'center', justifyContent: 'center',
+        }}
+      >
+        {/* Статический thumbnail через Image (первый кадр если платформа
+            поддерживает, иначе чёрный фон). Реальное видео играет только
+            в Modal ради производительности FlatList'а. */}
+        <Image
+          source={{ uri }}
+          style={{ width: '100%', height: '100%' }}
+          resizeMode="cover"
+        />
+        <View
+          style={{
+            position: 'absolute',
+            width: 52, height: 52, borderRadius: 26,
+            backgroundColor: 'rgba(0,0,0,0.55)',
+            alignItems: 'center', justifyContent: 'center',
+          }}
+        >
+          <Ionicons name="play" size={22} color="#ffffff" style={{ marginLeft: 2 }} />
+        </View>
+        {duration !== undefined && (
+          <View
+            style={{
+              position: 'absolute',
+              right: size / 2 - 26, bottom: 16,
+              paddingHorizontal: 6, paddingVertical: 2,
+              borderRadius: 6,
+              backgroundColor: 'rgba(0,0,0,0.6)',
+            }}
+          >
+            <Text style={{ color: '#ffffff', fontSize: 11, fontWeight: '600' }}>
+              {formatClock(duration)}
+            </Text>
+          </View>
+        )}
+      </Pressable>
+
+      {open && (
+        <VideoModal uri={uri} onClose={() => setOpen(false)} />
+      )}
+    </>
+  );
+}
+
+// Modal рендерится только когда open=true — это значит useVideoPlayer
+// не создаёт лишних плееров пока пользователь не открыл overlay.
+
+function VideoModal({ uri, onClose }: { uri: string; onClose: () => void }) {
+  // useVideoPlayer может throw'нуть на некоторых платформах при
+  // невалидных source'ах. try/catch вокруг render'а защищает парента
+  // от полного crash'а.
+  let player: ReturnType<typeof useVideoPlayer> | null = null;
+  try {
+    // eslint-disable-next-line react-hooks/rules-of-hooks
+    player = useVideoPlayer({ uri }, (p) => {
+      p.loop = true;
+      p.muted = false;
+      p.play();
+    });
+  } catch {
+    player = null;
+  }
+
+  return (
+    <Modal visible transparent animationType="fade" onRequestClose={onClose}>
+      <Pressable
+        onPress={onClose}
+        style={{
+          flex: 1,
+          backgroundColor: 'rgba(0,0,0,0.92)',
+          alignItems: 'center',
+          justifyContent: 'center',
+          padding: 20,
+        }}
+      >
+        <View
+          style={{
+            width: '90%',
+            aspectRatio: 1,
+            maxWidth: 420, maxHeight: 420,
+            borderRadius: 9999,
+            overflow: 'hidden',
+            backgroundColor: '#000',
+          }}
+        >
+          {player ? (
+            <VideoView
+              player={player}
+              style={{ width: '100%', height: '100%' }}
+              contentFit="cover"
+              nativeControls={false}
+            />
+          ) : (
+            <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
+              <Ionicons name="alert-circle-outline" size={36} color="#8b8b8b" />
+              <Text style={{ color: '#8b8b8b', fontSize: 12, marginTop: 8 }}>
+                Playback not available
+              </Text>
+            </View>
+          )}
+        </View>
+
+        <Pressable
+          onPress={onClose}
+          style={{
+            position: 'absolute',
+            top: 48, right: 16,
+            width: 40, height: 40, borderRadius: 20,
+            backgroundColor: 'rgba(255,255,255,0.14)',
+            alignItems: 'center', justifyContent: 'center',
+          }}
+        >
+          <Ionicons name="close" size={22} color="#ffffff" />
+        </Pressable>
+      </Pressable>
+    </Modal>
+  );
+}