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/VideoCircleRecorder.tsx

@@ -0,0 +1,217 @@
+/**
+ * VideoCircleRecorder — full-screen Modal для записи круглого видео-
+ * сообщения (Telegram-style).
+ *
+ * UX:
+ *   1. Открывается Modal с CameraView (по умолчанию front-camera).
+ *   2. Превью — круглое (аналогично VideoCirclePlayer).
+ *   3. Большая красная кнопка внизу: tap-to-start, tap-to-stop.
+ *   4. Максимум 15 секунд — авто-стоп.
+ *   5. По stop'у возвращаем attachment { kind:'video', circle:true, uri, duration }.
+ *   6. Свайп вниз / close-icon → cancel (без отправки).
+ */
+import React, { useEffect, useRef, useState } from 'react';
+import { View, Text, Pressable, Modal, Alert } from 'react-native';
+import { Ionicons } from '@expo/vector-icons';
+import { useSafeAreaInsets } from 'react-native-safe-area-context';
+import { CameraView, useCameraPermissions, useMicrophonePermissions } from 'expo-camera';
+
+import type { Attachment } from '@/lib/types';
+
+export interface VideoCircleRecorderProps {
+  visible: boolean;
+  onClose: () => void;
+  onFinish: (att: Attachment) => void;
+}
+
+const MAX_DURATION_SEC = 15;
+
+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 VideoCircleRecorder({ visible, onClose, onFinish }: VideoCircleRecorderProps) {
+  const insets = useSafeAreaInsets();
+  const camRef = useRef<CameraView>(null);
+
+  const [camPerm, requestCam] = useCameraPermissions();
+  const [micPerm, requestMic] = useMicrophonePermissions();
+
+  const [recording, setRecording] = useState(false);
+  const [elapsed, setElapsed]     = useState(0);
+  const startedAt = useRef(0);
+  const facing: 'front' | 'back' = 'front';
+
+  // Timer + auto-stop at MAX_DURATION_SEC
+  useEffect(() => {
+    if (!recording) return;
+    const t = setInterval(() => {
+      const s = Math.floor((Date.now() - startedAt.current) / 1000);
+      setElapsed(s);
+      if (s >= MAX_DURATION_SEC) stopAndSend();
+    }, 250);
+    return () => clearInterval(t);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [recording]);
+
+  // Permissions on mount of visible
+  useEffect(() => {
+    if (!visible) {
+      setRecording(false);
+      setElapsed(0);
+      return;
+    }
+    (async () => {
+      if (!camPerm?.granted) await requestCam();
+      if (!micPerm?.granted) await requestMic();
+    })();
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [visible]);
+
+  const start = async () => {
+    if (!camRef.current || recording) return;
+    try {
+      startedAt.current = Date.now();
+      setElapsed(0);
+      setRecording(true);
+      // recordAsync блокируется до stopRecording или maxDuration
+      const result = await camRef.current.recordAsync({ maxDuration: MAX_DURATION_SEC });
+      setRecording(false);
+      if (!result?.uri) return;
+      const seconds = Math.max(1, Math.floor((Date.now() - startedAt.current) / 1000));
+      onFinish({
+        kind:     'video',
+        circle:   true,
+        uri:      result.uri,
+        duration: seconds,
+        mime:     'video/mp4',
+      });
+      onClose();
+    } catch (e: any) {
+      setRecording(false);
+      Alert.alert('Recording failed', e?.message ?? 'Unknown error');
+    }
+  };
+
+  const stopAndSend = () => {
+    if (!recording) return;
+    camRef.current?.stopRecording();
+    // recordAsync promise выше resolve'нется с uri → onFinish
+  };
+
+  const cancel = () => {
+    if (recording) {
+      camRef.current?.stopRecording();
+    }
+    onClose();
+  };
+
+  const permOK = camPerm?.granted && micPerm?.granted;
+
+  return (
+    <Modal visible={visible} transparent animationType="slide" onRequestClose={cancel}>
+      <View
+        style={{
+          flex: 1,
+          backgroundColor: '#000000',
+          paddingTop: insets.top,
+          paddingBottom: Math.max(insets.bottom, 12),
+        }}
+      >
+        {/* Header */}
+        <View style={{ flexDirection: 'row', alignItems: 'center', padding: 12 }}>
+          <Pressable
+            onPress={cancel}
+            hitSlop={10}
+            style={{
+              width: 36, height: 36, borderRadius: 18,
+              backgroundColor: 'rgba(255,255,255,0.08)',
+              alignItems: 'center', justifyContent: 'center',
+            }}
+          >
+            <Ionicons name="close" size={20} color="#ffffff" />
+          </Pressable>
+          <Text style={{ color: '#ffffff', fontSize: 16, fontWeight: '700', flex: 1, textAlign: 'center' }}>
+            Video message
+          </Text>
+          <View style={{ width: 36 }} />
+        </View>
+
+        {/* Camera */}
+        <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center', padding: 20 }}>
+          {permOK ? (
+            <View
+              style={{
+                width: '85%',
+                aspectRatio: 1,
+                maxWidth: 360, maxHeight: 360,
+                borderRadius: 9999,
+                overflow: 'hidden',
+                backgroundColor: '#0a0a0a',
+                borderWidth: recording ? 3 : 0,
+                borderColor: '#f4212e',
+              }}
+            >
+              <CameraView
+                ref={camRef}
+                style={{ flex: 1 }}
+                facing={facing}
+                mode="video"
+              />
+            </View>
+          ) : (
+            <View style={{ alignItems: 'center', paddingHorizontal: 24 }}>
+              <Ionicons name="videocam-off-outline" size={42} color="#8b8b8b" />
+              <Text style={{ color: '#ffffff', fontSize: 16, fontWeight: '700', marginTop: 12 }}>
+                Permissions needed
+              </Text>
+              <Text style={{ color: '#8b8b8b', fontSize: 13, marginTop: 4, textAlign: 'center' }}>
+                Camera + microphone access are required to record a video message.
+              </Text>
+            </View>
+          )}
+
+          {/* Timer */}
+          {recording && (
+            <Text
+              style={{
+                color: '#f4212e',
+                fontSize: 14, fontWeight: '700',
+                marginTop: 14,
+              }}
+            >
+              ● {formatClock(elapsed)} / {formatClock(MAX_DURATION_SEC)}
+            </Text>
+          )}
+        </View>
+
+        {/* Record / Stop button */}
+        <View style={{ alignItems: 'center', paddingBottom: 16 }}>
+          <Pressable
+            onPress={recording ? stopAndSend : start}
+            disabled={!permOK}
+            style={({ pressed }) => ({
+              width: 72, height: 72, borderRadius: 36,
+              backgroundColor: !permOK ? '#1a1a1a' : recording ? '#f4212e' : '#1d9bf0',
+              alignItems: 'center', justifyContent: 'center',
+              opacity: pressed ? 0.85 : 1,
+              borderWidth: 4,
+              borderColor: 'rgba(255,255,255,0.2)',
+            })}
+          >
+            <Ionicons
+              name={recording ? 'stop' : 'videocam'}
+              size={30}
+              color="#ffffff"
+            />
+          </Pressable>
+          <Text style={{ color: '#8b8b8b', fontSize: 12, marginTop: 10 }}>
+            {recording ? 'Tap to stop & send' : permOK ? 'Tap to record' : 'Grant permissions'}
+          </Text>
+        </View>
+      </View>
+    </Modal>
+  );
+}