fix(feed): card spacing, action-row distribution, tab strip, detail inset

- PostCard rows got cramped paddings and a near-invisible divider.
  Increased paddingTop 12→16, paddingBottom 12→18, paddingHorizontal
  14→16; divider colour #141414→#222222 so the seam between posts is
  legible on OLED blacks.
- Action row (chat / ❤ / view / share) used a fixed gap:32 + spacer.
  Reworked to four flex:1 cells with justifyContent: space-between,
  so the first three icons distribute evenly across the row and share
  pins to the right edge. Matches Twitter's layout where each action
  occupies a quarter of the row regardless of label width.
- Feed tab strip (Подписки / Для вас / В тренде) used flex:1 +
  gap:10 which bunched the three labels together visually. Switched
  to justifyContent: space-between + paddingHorizontal:20 so each
  tab hugs its label and the three labels spread to the edges with
  full horizontal breathing room.
- Post detail screen (/feed/[id]) and hashtag feed (/feed/tag/[tag])
  were missing the safe-area top inset — their headers butted right
  against the status bar / notch. Added useSafeAreaInsets().top as
  paddingTop on the outer View, matching the rest of the app.

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

client-app/app/(app)/feed/[id].tsx

@@ -21,6 +21,7 @@ import {
 } from 'react-native';
 import { Ionicons } from '@expo/vector-icons';
 import { router, useLocalSearchParams } from 'expo-router';
+import { useSafeAreaInsets } from 'react-native-safe-area-context';
 
 import { Header } from '@/components/Header';
 import { IconButton } from '@/components/IconButton';
@@ -32,6 +33,7 @@ import {
 } from '@/lib/feed';
 
 export default function PostDetailScreen() {
+  const insets = useSafeAreaInsets();
   const { id: postID } = useLocalSearchParams<{ id: string }>();
   const keyFile = useStore(s => s.keyFile);
 
@@ -73,7 +75,7 @@ export default function PostDetailScreen() {
   }, []);
 
   return (
-    <View style={{ flex: 1, backgroundColor: '#000000' }}>
+    <View style={{ flex: 1, backgroundColor: '#000000', paddingTop: insets.top }}>
       <Header
         divider
         left={<IconButton icon="chevron-back" size={36} onPress={() => router.back()} />}