refactor(search): extract shared code to commons, remove dead code

- Extract DateUtils (isLeapYear, dateToUnix, timestampToDate) to deduplicate
  identical implementations in QueryParser and QuerySerializer
- Move SavedSearch data class from desktopApp to commons/search
- Replace local formatTimestamp with existing toTimeAgo from commons/util
- Remove dead code: resolveAuthorName, _authorSuggestions (never called)
- Remove dead code: createOrFilters (never wired into SearchScreen)
- Remove unused ICacheProvider dependency from AdvancedSearchBarState

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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

@@ -22,6 +22,7 @@ package com.vitorpamplona.amethyst.desktop
 
 import com.vitorpamplona.amethyst.commons.search.QueryParser
 import com.vitorpamplona.amethyst.commons.search.QuerySerializer
+import com.vitorpamplona.amethyst.commons.search.SavedSearch
 import com.vitorpamplona.amethyst.commons.search.SearchQuery
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
@@ -134,10 +135,3 @@ object SearchHistoryStore {
         prefs.put(KEY_SAVED, raw)
     }
 }
-
-data class SavedSearch(
-    val id: String,
-    val label: String,
-    val query: SearchQuery,
-    val createdAt: Long,
-)

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/subscriptions/SearchFilterFactory.kt

@@ -128,19 +128,6 @@ object SearchFilterFactory {
         }
     }
 
-    fun createOrFilters(
-        query: SearchQuery,
-        limit: Int = 100,
-    ): List<List<Filter>> {
-        if (query.orTerms.isEmpty()) return listOf(createFilters(query, limit))
-
-        // Each OR term gets its own set of filters
-        return query.orTerms.take(3).map { term ->
-            val termQuery = query.copy(text = term, orTerms = kotlinx.collections.immutable.persistentListOf())
-            createFilters(termQuery, limit)
-        }
-    }
-
     private fun buildSearchString(query: SearchQuery): String? {
         val parts = mutableListOf<String>()
 

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

@@ -111,7 +111,7 @@ fun SearchScreen(
     modifier: Modifier = Modifier,
 ) {
     val scope = rememberCoroutineScope()
-    val state = remember { AdvancedSearchBarState(localCache, scope) }
+    val state = remember { AdvancedSearchBarState(scope) }
     val focusRequester = remember { FocusRequester() }
 
     // Pre-fill initial query
@@ -408,7 +408,7 @@ fun SearchScreen(
 @Composable
 private fun SearchEmptyState(
     historyItems: List<com.vitorpamplona.amethyst.commons.search.SearchQuery>,
-    savedSearches: List<com.vitorpamplona.amethyst.desktop.SavedSearch>,
+    savedSearches: List<com.vitorpamplona.amethyst.commons.search.SavedSearch>,
     onLoadQuery: (com.vitorpamplona.amethyst.commons.search.SearchQuery) -> Unit,
     onDeleteSaved: (String) -> Unit,
     onClearHistory: () -> Unit,

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

@@ -62,6 +62,7 @@ import androidx.compose.ui.unit.dp
 import com.vitorpamplona.amethyst.commons.search.AdvancedSearchBarState
 import com.vitorpamplona.amethyst.commons.search.KindRegistry
 import com.vitorpamplona.amethyst.commons.ui.components.UserSearchCard
+import com.vitorpamplona.amethyst.commons.util.toTimeAgo
 import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip23LongContent.LongTextNoteEvent
 
@@ -255,7 +256,7 @@ private fun NotePreviewCard(
                 Spacer(Modifier.weight(1f))
                 // Timestamp
                 Text(
-                    formatTimestamp(event.createdAt),
+                    event.createdAt.toTimeAgo(withDot = false),
                     style = MaterialTheme.typography.bodySmall,
                     color = MaterialTheme.colorScheme.onSurfaceVariant,
                 )
@@ -296,32 +297,3 @@ private fun <T> ExpandableSection(
         }
     }
 }
-
-private fun formatTimestamp(ts: Long): String {
-    val now = System.currentTimeMillis() / 1000
-    val diff = now - ts
-    return when {
-        diff < 60 -> {
-            "just now"
-        }
-
-        diff < 3600 -> {
-            "${diff / 60}m ago"
-        }
-
-        diff < 86400 -> {
-            "${diff / 3600}h ago"
-        }
-
-        diff < 604800 -> {
-            "${diff / 86400}d ago"
-        }
-
-        else -> {
-            // Simple date format
-            val days = ts / 86400
-            val year = 1970 + (days / 365).toInt()
-            "$year"
-        }
-    }
-}