fix(desktop): wire Open Full Search via LocalOpenFullSearch CompositionLocal

- Add LocalOpenFullSearch CompositionLocal (navigates to Search column)
- Provided at Main.kt level alongside LocalFeedSearchActive
- FeedScreen reads it directly — no param threading needed
- "Open full search" link in expanded header now actually opens Search column
- Removed unused onOpenSearch param from DeckColumnContainer

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/Main.kt

@@ -452,7 +452,9 @@ fun main() {
                             } else {
                                 KeyShortcut(Key.F, ctrl = true)
                             },
-                        onClick = { feedSearchActiveState.value = !feedSearchActiveState.value },
+                        onClick = {
+                            feedSearchActiveState.value = !feedSearchActiveState.value
+                        },
                     )
                     Item(
                         "App Drawer",
@@ -620,6 +622,9 @@ fun main() {
                 key(appRestartKey) {
                     CompositionLocalProvider(
                         com.vitorpamplona.amethyst.desktop.ui.theme.LocalFeedSearchActive provides feedSearchActiveState,
+                        com.vitorpamplona.amethyst.desktop.ui.theme.LocalOpenFullSearch provides {
+                            navigateToScreen?.invoke(DeckColumnType.Search)
+                        },
                     ) {
                         App(
                             layoutMode = layoutMode,

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/ui/FeedScreen.kt

@@ -342,6 +342,7 @@ fun FeedScreen(
     val feedSearchActiveState = com.vitorpamplona.amethyst.desktop.ui.theme.LocalFeedSearchActive.current
     var searchActive by feedSearchActiveState
     val onSearchActiveChange: (Boolean) -> Unit = { searchActive = it }
+    val openFullSearch = com.vitorpamplona.amethyst.desktop.ui.theme.LocalOpenFullSearch.current
     val relayStatuses by relayManager.relayStatuses.collectAsState()
     val connectedRelays by relayManager.connectedRelays.collectAsState()
     val followedUsers by localCache.followedUsers.collectAsState()
@@ -789,7 +790,7 @@ fun FeedScreen(
             },
             onOpenFeedsDrawer = onOpenFeedsDrawer,
             onCompose = onCompose,
-            onSearchClick = onSearchClick,
+            onSearchClick = openFullSearch,
             relayManager = relayManager,
             localCache = localCache,
             onNavigateToProfile = onNavigateToProfile,

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/ui/theme/AmethystSpacing.kt

@@ -53,6 +53,9 @@ val LocalIsDarkTheme = staticCompositionLocalOf { false }
 /** Mutable state for Cmd+F feed search. Provided at Main.kt level. */
 val LocalFeedSearchActive = compositionLocalOf { mutableStateOf(false) }
 
+/** Callback to open the full Search column/screen. Provided at Main.kt level. */
+val LocalOpenFullSearch = compositionLocalOf<() -> Unit> { {} }
+
 val MaterialTheme.spacing: AmethystSpacing
     @Composable @ReadOnlyComposable
     get() = LocalSpacing.current