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/hooks/useGlobalInbox.ts

@@ -0,0 +1,114 @@
+/**
+ * useGlobalInbox — app-wide inbox listener.
+ *
+ * Подписан на WS-топик `inbox:<my_x25519>` при любом экране внутри
+ * (app)-группы. Когда приходит push с envelope, мы:
+ *   1. Декриптуем — если это наш контакт, добавляем в store.
+ *   2. Инкрементим unreadByContact[address].
+ *   3. Показываем local notification (от кого + счётчик).
+ *
+ * НЕ дублирует chat-detail'овский `useMessages` — тот делает initial
+ * HTTP-pull при открытии чата и слушает тот же топик (двойная подписка
+ * с фильтром по sender_pub). Оба держат в store консистентное состояние
+ * через `appendMessage` (который идемпотентен по id).
+ *
+ * Фильтрация "app backgrounded" не нужна: Expo notifications'handler
+ * показывает banner и в foreground, но при активном чате с этим
+ * контактом нотификация dismiss'ится автоматически через
+ * clearContactNotifications (вызывается при mount'е chats/[id]).
+ */
+import { useEffect, useRef } from 'react';
+import { AppState } from 'react-native';
+import { usePathname } from 'expo-router';
+
+import { useStore } from '@/lib/store';
+import { getWSClient } from '@/lib/ws';
+import { decryptMessage } from '@/lib/crypto';
+import { fetchInbox } from '@/lib/api';
+import { appendMessage } from '@/lib/storage';
+import { randomId } from '@/lib/utils';
+
+import { notifyIncoming } from './useNotifications';
+
+export function useGlobalInbox() {
+  const keyFile    = useStore(s => s.keyFile);
+  const contacts   = useStore(s => s.contacts);
+  const appendMsg  = useStore(s => s.appendMessage);
+  const incrementUnread = useStore(s => s.incrementUnread);
+  const pathname   = usePathname();
+  const contactsRef = useRef(contacts);
+  const pathnameRef = useRef(pathname);
+
+  useEffect(() => { contactsRef.current = contacts; }, [contacts]);
+  useEffect(() => { pathnameRef.current = pathname; }, [pathname]);
+
+  useEffect(() => {
+    if (!keyFile?.x25519_pub) return;
+
+    const ws = getWSClient();
+
+    const handleEnvelopePull = async () => {
+      try {
+        const envelopes = await fetchInbox(keyFile.x25519_pub);
+        for (const env of envelopes) {
+          // Найти контакт по sender_pub — если не знакомый, игнорим
+          // (для MVP; в future можно показывать "unknown sender").
+          const c = contactsRef.current.find(
+            x => x.x25519Pub === env.sender_pub,
+          );
+          if (!c) continue;
+
+          let text = '';
+          try {
+            text = decryptMessage(
+              env.ciphertext,
+              env.nonce,
+              env.sender_pub,
+              keyFile.x25519_priv,
+            ) ?? '';
+          } catch {
+            continue;
+          }
+          if (!text) continue;
+
+          // Стабильный id от сервера (sha256(nonce||ct)[:16]); fallback
+          // на nonce-префикс если вдруг env.id пустой.
+          const msgId = env.id || `${env.sender_pub}_${env.nonce.slice(0, 16)}`;
+          const msg = {
+            id:        msgId,
+            from:      env.sender_pub,
+            text,
+            timestamp: env.timestamp,
+            mine:      false,
+          };
+          appendMsg(c.address, msg);
+          await appendMessage(c.address, msg);
+
+          // Если пользователь прямо сейчас в этом чате — unread не инкрементим,
+          // notification не показываем.
+          const inThisChat =
+            pathnameRef.current === `/chats/${c.address}` ||
+            pathnameRef.current.startsWith(`/chats/${c.address}/`);
+          if (inThisChat && AppState.currentState === 'active') continue;
+
+          incrementUnread(c.address);
+          const unread = useStore.getState().unreadByContact[c.address] ?? 1;
+          notifyIncoming({
+            contactAddress: c.address,
+            senderName:     c.username ? `@${c.username}` : (c.alias ?? 'New message'),
+            unreadCount:    unread,
+          });
+        }
+      } catch {
+        /* silent — ошибки pull'а обрабатывает useMessages */
+      }
+    };
+
+    const off = ws.subscribe('inbox:' + keyFile.x25519_pub, (frame) => {
+      if (frame.event !== 'inbox') return;
+      handleEnvelopePull();
+    });
+
+    return off;
+  }, [keyFile, appendMsg, incrementUnread]);
+}