remove :storage-ksqlite (conversation/message) and related tests; decouple schema from journal

journal-inmemory/src/commonMain/kotlin/pw/binom/agentik/journal/inmemory/InMemoryJournalStore.kt

@@ -54,9 +54,9 @@ class InMemoryJournalStore : MutableJournalStore {
             .toList()
     }
 
-    /** Сбросить кэш (например, когда диалог удалён). */
-    suspend fun clear(): Unit = mutex.withLock {
-        records.clear()
+    /** Удалить все записи диалога (каскад из ChatAgent.deleteConversation). */
+    override suspend fun clear(conversationId: String): Unit = mutex.withLock {
+        records.removeAll { it.conversationId == conversationId }
     }
 
     /** Сколько записей сейчас в кэше. Для тестов/диагностики. */

journal-inmemory/src/commonMain/kotlin/pw/binom/agentik/journal/inmemory/InMemoryMutableConversationStore.kt

@@ -29,7 +29,7 @@ class InMemoryMutableConversationStore(
     private val clock: Clock = Clock.System,
 ) : MutableConversationStore {
 
-    private val byId: MutableMap<String, ConversationRecord> = mutableMapOf()
+    private val byId = mutableMapOf<String, ConversationRecord>()
     private val mutex = Mutex()
 
     override suspend fun upsert(record: ConversationRecord) {

journal-inmemory/src/commonTest/kotlin/pw/binom/agentik/journal/inmemory/InMemoryJournalStoreTest.kt

@@ -66,13 +66,15 @@ class InMemoryJournalStoreTest {
     }
 
     @Test
-    fun `clear empties the cache`() = runTest {
+    fun `clear empties a conversation only`() = runTest {
         val store = InMemoryJournalStore()
         val t0 = Instant.parse("2026-09-21T10:00:00Z")
         store.append(userMsg("m1", "c1", "x", t0))
+        store.append(userMsg("m2", "c2", "y", t0))
+        assertEquals(2, store.size())
+        store.clear("c1")
         assertEquals(1, store.size())
-        store.clear()
-        assertEquals(0, store.size())
         assertTrue(store.list("c1", Instant.DISTANT_PAST, 0, 100).isEmpty())
+        assertEquals(listOf("m2"), store.list("c2", Instant.DISTANT_PAST, 0, 100).map { it.id })
     }
 }