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/AttachmentMenu.tsx

@@ -0,0 +1,188 @@
+/**
+ * AttachmentMenu — bottom-sheet с вариантами прикрепления.
+ *
+ * Выводится при нажатии на `+` в composer'е. Опции:
+ *   - 📷 Photo / video из галереи (expo-image-picker)
+ *   - 📸 Take photo (камера)
+ *   - 📎 File (expo-document-picker)
+ *   - 🎙️ Voice message — stub (запись через expo-av потребует
+ *        permissions runtime + recording UI; сейчас добавляет мок-
+ *        голосовое с duration 4s)
+ *
+ * Всё визуально — тёмный overlay + sheet снизу. Закрытие по tap'у на
+ * overlay или на Cancel.
+ */
+import React from 'react';
+import { View, Text, Pressable, Alert, Modal } from 'react-native';
+import { Ionicons } from '@expo/vector-icons';
+import { useSafeAreaInsets } from 'react-native-safe-area-context';
+import * as ImagePicker from 'expo-image-picker';
+import * as DocumentPicker from 'expo-document-picker';
+
+import type { Attachment } from '@/lib/types';
+
+export interface AttachmentMenuProps {
+  visible: boolean;
+  onClose: () => void;
+  /** Вызывается когда attachment готов для отправки. */
+  onPick:  (att: Attachment) => void;
+}
+
+export function AttachmentMenu({ visible, onClose, onPick }: AttachmentMenuProps) {
+  const insets = useSafeAreaInsets();
+
+  const pickImageOrVideo = async () => {
+    try {
+      const perm = await ImagePicker.requestMediaLibraryPermissionsAsync();
+      if (!perm.granted) {
+        Alert.alert('Permission needed', 'Grant photos access to attach media.');
+        return;
+      }
+      const result = await ImagePicker.launchImageLibraryAsync({
+        mediaTypes:    ImagePicker.MediaTypeOptions.All,
+        quality:       0.85,
+        allowsEditing: false,
+      });
+      if (result.canceled) return;
+      const asset = result.assets[0];
+      onPick({
+        kind:     asset.type === 'video' ? 'video' : 'image',
+        uri:      asset.uri,
+        mime:     asset.mimeType,
+        width:    asset.width,
+        height:   asset.height,
+        duration: asset.duration ? Math.round(asset.duration / 1000) : undefined,
+      });
+      onClose();
+    } catch (e: any) {
+      Alert.alert('Pick failed', e?.message ?? 'Unknown error');
+    }
+  };
+
+  const takePhoto = async () => {
+    try {
+      const perm = await ImagePicker.requestCameraPermissionsAsync();
+      if (!perm.granted) {
+        Alert.alert('Permission needed', 'Grant camera access to take a photo.');
+        return;
+      }
+      const result = await ImagePicker.launchCameraAsync({ quality: 0.85 });
+      if (result.canceled) return;
+      const asset = result.assets[0];
+      onPick({
+        kind:   asset.type === 'video' ? 'video' : 'image',
+        uri:    asset.uri,
+        mime:   asset.mimeType,
+        width:  asset.width,
+        height: asset.height,
+      });
+      onClose();
+    } catch (e: any) {
+      Alert.alert('Camera failed', e?.message ?? 'Unknown error');
+    }
+  };
+
+  const pickFile = async () => {
+    try {
+      const res = await DocumentPicker.getDocumentAsync({
+        type: '*/*',
+        copyToCacheDirectory: true,
+      });
+      if (res.canceled) return;
+      const asset = res.assets[0];
+      onPick({
+        kind: 'file',
+        uri:  asset.uri,
+        name: asset.name,
+        mime: asset.mimeType ?? undefined,
+        size: asset.size,
+      });
+      onClose();
+    } catch (e: any) {
+      Alert.alert('File pick failed', e?.message ?? 'Unknown error');
+    }
+  };
+
+  // Voice recorder больше не stub — см. inline-кнопку 🎤 в composer'е,
+  // которая разворачивает VoiceRecorder (expo-av Audio.Recording). Опция
+  // Voice в этом меню убрана, т.к. дублировала бы UX.
+
+  return (
+    <Modal visible={visible} transparent animationType="slide" onRequestClose={onClose}>
+      <Pressable
+        onPress={onClose}
+        style={{ flex: 1, backgroundColor: 'rgba(0,0,0,0.55)' }}
+      >
+        <View style={{ flex: 1 }} />
+        <Pressable
+          onPress={() => {}}
+          style={{
+            backgroundColor: '#111111',
+            borderTopLeftRadius: 20,
+            borderTopRightRadius: 20,
+            paddingTop: 8,
+            paddingBottom: Math.max(insets.bottom, 12) + 10,
+            paddingHorizontal: 10,
+            borderTopWidth: 1, borderColor: '#1f1f1f',
+          }}
+        >
+          {/* Drag handle */}
+          <View
+            style={{
+              alignSelf: 'center',
+              width: 40, height: 4, borderRadius: 2,
+              backgroundColor: '#2a2a2a',
+              marginBottom: 12,
+            }}
+          />
+          <Text
+            style={{
+              color: '#ffffff', fontSize: 16, fontWeight: '700',
+              marginLeft: 8, marginBottom: 12,
+            }}
+          >
+            Attach
+          </Text>
+
+          <Row icon="images-outline" label="Photo / video"      onPress={pickImageOrVideo} />
+          <Row icon="camera-outline" label="Take photo"         onPress={takePhoto} />
+          <Row icon="document-outline" label="File"             onPress={pickFile} />
+        </Pressable>
+      </Pressable>
+    </Modal>
+  );
+}
+
+function Row({
+  icon, label, onPress,
+}: {
+  icon: React.ComponentProps<typeof Ionicons>['name'];
+  label: string;
+  onPress: () => void;
+}) {
+  return (
+    <Pressable
+      onPress={onPress}
+      style={({ pressed }) => ({
+        flexDirection: 'row',
+        alignItems: 'center',
+        gap: 14,
+        paddingHorizontal: 14,
+        paddingVertical: 14,
+        borderRadius: 14,
+        backgroundColor: pressed ? '#1a1a1a' : 'transparent',
+      })}
+    >
+      <View
+        style={{
+          width: 40, height: 40, borderRadius: 10,
+          backgroundColor: '#1a1a1a',
+          alignItems: 'center', justifyContent: 'center',
+        }}
+      >
+        <Ionicons name={icon} size={20} color="#ffffff" />
+      </View>
+      <Text style={{ color: '#ffffff', fontSize: 15, fontWeight: '600' }}>{label}</Text>
+    </Pressable>
+  );
+}