feat(desktop): Messages-style headers across every remaining screen

Rolled the compact header pattern out to the screens the earlier pass
missed. Each one now lives on the same padding/typography rhythm as
Messages: Row(fillMaxWidth, padding horizontal = 12, vertical = 8),
titleMedium for labels, IconButton size = 32dp with 20dp icons tinted
with colorScheme.primary.

- ThreadScreen: back button + "Thread" title. Was headlineMedium with
  bottom-only padding; now compact row.
- UserProfileScreen: back + "Profile" title on the left, Edit /
  Follow buttons kept on the right (they stay as text buttons — they
  represent destructive intent, not icon affordances).
- ArticleReaderScreen: back + "Article" title; zoom % label still
  surfaces next to the title when != 100%.
- ArticleEditorScreen: back IconButton + "Article" title (was a text
  "Back" OutlinedButton with no title). Save / Publish buttons kept
  on the right — same reasoning as UserProfileScreen.
- ChessScreen: back (conditional) + "Chess" / "Live Game" title;
  refresh + New Game converted from Button → IconButton so the
  header reads at the same scale as the rest.
- RelayDashboardScreen: had no header at all, just a PrimaryTabRow.
  Converted Monitor / Configure to FilterChip tabs-first (matching
  Feed / Reads) so the selected tab is the title.

FeedHeader relocation:
- Moved commons/ui/feed/FeedHeader.kt → desktopApp/ui/FeedHeader.kt.
  Only NotificationsScreen.kt referenced it, and dropping the import
  from that file was enough because it's now in the same package.
- Removed the empty commons/ui/feed/ directory.

https://claude.ai/code/session_01NufduPfZvYQVYwLkbCjCUo

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/ui/feed/FeedHeader.kt

@@ -1,80 +0,0 @@
-/*
- * Copyright (c) 2025 Vitor Pamplona
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy of
- * this software and associated documentation files (the "Software"), to deal in
- * the Software without restriction, including without limitation the rights to use,
- * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
- * Software, and to permit persons to whom the Software is furnished to do so,
- * subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
- * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
- * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
- * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
- * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- */
-package com.vitorpamplona.amethyst.commons.ui.feed
-
-import androidx.compose.foundation.layout.Arrangement
-import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.fillMaxWidth
-import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.layout.size
-import androidx.compose.material3.Icon
-import androidx.compose.material3.IconButton
-import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.Text
-import androidx.compose.runtime.Composable
-import androidx.compose.ui.Alignment
-import androidx.compose.ui.Modifier
-import androidx.compose.ui.unit.dp
-import com.vitorpamplona.amethyst.commons.icons.symbols.Icon
-import com.vitorpamplona.amethyst.commons.icons.symbols.MaterialSymbols
-
-/**
- * Compact Messages-style header for feed screens: titleMedium on the left,
- * a single refresh IconButton on the right. Relay count is rolled into the
- * refresh button's content description so it still surfaces in hover tooltips
- * / accessibility readers without stealing a whole row.
- *
- * @param title The feed title
- * @param connectedRelayCount Number of connected relays
- * @param onRefresh Callback when refresh button is clicked
- * @param modifier Modifier for the header row
- */
-@Composable
-fun FeedHeader(
-    title: String,
-    connectedRelayCount: Int,
-    onRefresh: () -> Unit,
-    modifier: Modifier = Modifier,
-) {
-    Row(
-        modifier = modifier.fillMaxWidth().padding(horizontal = 12.dp, vertical = 8.dp),
-        horizontalArrangement = Arrangement.SpaceBetween,
-        verticalAlignment = Alignment.CenterVertically,
-    ) {
-        Text(
-            title,
-            style = MaterialTheme.typography.titleMedium,
-            color = MaterialTheme.colorScheme.onBackground,
-        )
-
-        IconButton(
-            onClick = onRefresh,
-            modifier = Modifier.size(32.dp),
-        ) {
-            Icon(
-                MaterialSymbols.Refresh,
-                contentDescription = "Refresh ($connectedRelayCount relays connected)",
-                tint = MaterialTheme.colorScheme.primary,
-                modifier = Modifier.size(20.dp),
-            )
-        }
-    }
-}