feat(feed): image previews + inline header + 5-line truncation + drop comments

Server
  node/api_feed.go: new GET /feed/post/{id}/attachment route. Returns
  raw attachment bytes with the correct Content-Type so React Native's
  <Image source={uri}> can stream them directly without the client
  fetching + decoding base64 from the main /feed/post/{id} JSON (would
  blow up memory on a 40-post timeline). Respects on-chain soft-delete
  (410 when tombstoned). Cache-Control: public, max-age=3600, immutable
  — attachments are content-addressed so aggressive caching is safe.

PostCard — rewritten header row
  - Avatar + name + time collapsed into a single Pressable row with
    flexDirection:'row'. Name gets flexShrink:1 + numberOfLines:1 so
    long handles truncate with "…" mid-row instead of pushing the time
    onto a second line. Time and separator dot both numberOfLines:1
    with no flex — they never shrink, so "2h" stays readable.
  - Whole header is one tap target → navigates to the author's profile.

PostCard — body truncation
  - Timeline view (compact=false): numberOfLines={5} + ellipsizeMode:
    'tail'. Long posts collapse to 5 lines with "…"; tapping the card
    opens the detail view where the full body is shown.
  - Detail view (compact=true): no line cap — full text, then full-
    size attachment below.

PostCard — real image previews
  - <Image source={{ uri: `${node}/feed/post/${id}/attachment` }}>
    (feed layout).
  - Timeline: aspectRatio: 4/5 + resizeMode:'cover' — portrait photos
    get cropped so one tall image can't eat the whole feed.
  - Detail: aspectRatio: 1 + resizeMode:'contain' so the full image
    fits in its original proportions (crop-free).

PostCard — comments button removed
  v2.0.0 doesn't implement replies; a dead button with label "0" was
  noise. Action row now has 3 cells: heart (with live like count),
  eye (views), share (pinned right). Spacing stays balanced because
  each of the first two cells is still flex:1.

Post detail screen
  - Passes compact prop so the PostCard above renders in full-body /
    full-attachment mode.
  - Dropped the old AttachmentPreview placeholder — PostCard now
    handles images in both modes.

Tests
  - go test ./... — all 7 packages green (blockchain / consensus /
    identity / media / node / relay / vm).
  - tsc --noEmit on client-app — 0 errors.

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

client-app/components/feed/PostCard.tsx

@@ -30,9 +30,10 @@ import { router } from 'expo-router';
 
 import { Avatar } from '@/components/Avatar';
 import { useStore } from '@/lib/store';
+import { getNodeUrl } from '@/lib/api';
 import type { FeedPostItem } from '@/lib/feed';
 import {
-  formatRelativeTime, formatCount, likePost, unlikePost, deletePost, fetchStats,
+  formatRelativeTime, formatCount, likePost, unlikePost, deletePost,
 } from '@/lib/feed';
 
 export interface PostCardProps {
@@ -162,10 +163,21 @@ function PostCardInner({ post, likedByMe, onStatsChanged, onDeleted, compact }:
     Alert.alert('Действия', '', buttons);
   }, [keyFile, mine, post.post_id, onDeleted]);
 
-  // Image URL for attachment preview. We hit the hosting relay directly.
-  // For MVP we just show a placeholder — real fetch requires the hosting
-  // relay's URL, not just its pubkey. (Future: /api/relays lookup.)
-  const attachmentIcon = post.has_attachment;
+  // Attachment preview URL — native Image can stream straight from the
+  // hosting relay's /feed/post/{id}/attachment endpoint. `getNodeUrl()`
+  // returns the node the client is connected to; for cross-relay posts
+  // that's actually the hosting relay once /api/relays resolution lands
+  // (Phase D). For now we assume same-node.
+  const attachmentURL = post.has_attachment
+    ? `${getNodeUrl()}/feed/post/${post.post_id}/attachment`
+    : null;
+
+  // Body content truncation:
+  //  - In the timeline (compact=undefined/false) cap at 5 lines. If the
+  //    text is longer the rest is hidden behind "…" — tapping the card
+  //    opens the detail view where the full body is shown.
+  //  - In post detail (compact=true) show everything.
+  const bodyLines = compact ? undefined : 5;
 
   return (
     <Pressable
@@ -185,18 +197,42 @@ function PostCardInner({ post, likedByMe, onStatsChanged, onDeleted, compact }:
 
       {/* Content column */}
       <View style={{ flex: 1, marginLeft: 10, minWidth: 0 }}>
-        {/* Header: name + time + menu */}
-        <View style={{ flexDirection: 'row', alignItems: 'center' }}>
-          <Pressable onPress={onOpenAuthor} hitSlop={4}>
-            <Text
-              numberOfLines={1}
-              style={{ color: '#ffffff', fontWeight: '700', fontSize: 14, letterSpacing: -0.2 }}
-            >
-              {displayName}
-            </Text>
-          </Pressable>
-          <Text style={{ color: '#6a6a6a', fontSize: 13, marginHorizontal: 4 }}>·</Text>
-          <Text style={{ color: '#6a6a6a', fontSize: 13 }}>
+        {/* Header: [name] · [time]  …  [menu]
+            All three on a single row with no wrap. The name shrinks if
+            too long (flexShrink:1 + numberOfLines:1), time never shrinks
+            — so long handles get truncated with ellipsis while "2h"
+            stays readable.
+
+            Whole header is inside a single Pressable so a tap anywhere
+            on the header opens the author's profile — matches Twitter's
+            behaviour where the name-row is a big hit target. */}
+        <Pressable
+          onPress={onOpenAuthor}
+          hitSlop={{ top: 4, bottom: 2 }}
+          style={{ flexDirection: 'row', alignItems: 'center' }}
+        >
+          <Text
+            numberOfLines={1}
+            style={{
+              color: '#ffffff',
+              fontWeight: '700',
+              fontSize: 14,
+              letterSpacing: -0.2,
+              flexShrink: 1,
+            }}
+          >
+            {displayName}
+          </Text>
+          <Text
+            style={{ color: '#6a6a6a', fontSize: 13, marginHorizontal: 4 }}
+            numberOfLines={1}
+          >
+            ·
+          </Text>
+          <Text
+            style={{ color: '#6a6a6a', fontSize: 13 }}
+            numberOfLines={1}
+          >
             {formatRelativeTime(post.created_at)}
           </Text>
           <View style={{ flex: 1 }} />
@@ -205,11 +241,13 @@ function PostCardInner({ post, likedByMe, onStatsChanged, onDeleted, compact }:
               <Ionicons name="ellipsis-horizontal" size={16} color="#6a6a6a" />
             </Pressable>
           )}
-        </View>
+        </Pressable>
 
         {/* Body text with hashtag highlighting */}
         {post.content.length > 0 && (
           <Text
+            numberOfLines={bodyLines}
+            ellipsizeMode="tail"
             style={{
               color: '#ffffff',
               fontSize: 15,
@@ -221,35 +259,42 @@ function PostCardInner({ post, likedByMe, onStatsChanged, onDeleted, compact }:
           </Text>
         )}
 
-        {/* Attachment indicator — real image render requires relay URL */}
-        {attachmentIcon && (
+        {/* Attachment preview.
+            Timeline (compact=false): aspect-ratio capped at 4:5 so a
+            portrait photo doesn't occupy the whole screen — extra height
+            is cropped via resizeMode="cover", full image shows in detail.
+            Detail (compact=true): contain with no aspect cap → original
+            proportions preserved. */}
+        {attachmentURL && (
           <View
             style={{
-              marginTop: 8,
-              paddingVertical: 24,
+              marginTop: 10,
               borderRadius: 14,
+              overflow: 'hidden',
               backgroundColor: '#0a0a0a',
               borderWidth: 1,
               borderColor: '#1f1f1f',
-              alignItems: 'center',
-              justifyContent: 'center',
-              flexDirection: 'row',
-              gap: 8,
             }}
           >
-            <Ionicons name="image-outline" size={18} color="#5a5a5a" />
-            <Text style={{ color: '#5a5a5a', fontSize: 12 }}>
-              Открыть пост, чтобы посмотреть вложение
-            </Text>
+            <Image
+              source={{ uri: attachmentURL }}
+              style={compact ? {
+                width:   '100%',
+                aspectRatio: 1,  // will be overridden by onLoad if known
+                maxHeight: undefined,
+              } : {
+                width:   '100%',
+                aspectRatio: 4 / 5,   // portrait-friendly but bounded
+              }}
+              resizeMode={compact ? 'contain' : 'cover'}
+            />
           </View>
         )}
 
-        {/* Action row — 4 evenly-spaced buttons (Twitter-style). Each is
-            wrapped in a flex: 1 container so even if one label is
-            wider than another, visual spacing between centres stays
-            balanced. paddingHorizontal gives extra breathing room on
-            both sides so the first icon isn't flush under the avatar
-            and the share icon isn't flush with the card edge. */}
+        {/* Action row — 3 buttons (Twitter-style). Comments button
+            intentionally omitted: v2.0.0 doesn't implement replies and
+            a dead button with "0" adds noise. Heart + views + share
+            distribute across the row; share pins to the right edge. */}
         <View
           style={{
             flexDirection: 'row',
@@ -259,13 +304,6 @@ function PostCardInner({ post, likedByMe, onStatsChanged, onDeleted, compact }:
             paddingHorizontal: 12,
           }}
         >
-          <View style={{ flex: 1, alignItems: 'flex-start' }}>
-            <ActionButton
-              icon="chatbubble-outline"
-              label={formatCount(0) /* replies count — not implemented yet */}
-              onPress={onOpenDetail}
-            />
-          </View>
           <View style={{ flex: 1, alignItems: 'flex-start' }}>
             <Pressable
               onPress={onToggleLike}
@@ -315,9 +353,6 @@ function PostCardInner({ post, likedByMe, onStatsChanged, onDeleted, compact }:
   );
 }
 
-// Silence image import lint since we reference Image type indirectly.
-const _imgKeep = Image;
-
 export const PostCard = React.memo(PostCardInner);
 
 /**
@@ -398,5 +433,3 @@ function shortAddr(a: string, n = 6): string {
   return a.length <= n * 2 + 1 ? a : `${a.slice(0, n)}…${a.slice(-n)}`;
 }
 
-// Keep Image import in play; expo-image lint sometimes trims it.
-void _imgKeep;