feat(agent): persist tool-calls in working memory + interrupt-safe close-recreate

Radical redesign of interrupt semantics (plan: docs/TOOLSETS-PLAN.md,
phase commit 7):

1. Storage (:storage-core + :storage-sqlite + :storage-inmemory):
   add WorkingMemoryEntry.ToolExchange(toolName, toolArgsJson, resultText,
   wasCancelled) — one row per tool-call. Survives restarts.

2. ChatConversation:
   - new fields: interrupted (AtomicBoolean), currentToolJob (Job?)
   - interrupt() теперь только сигнал: ставит флаг, cancel LiteConv +
     cancel currentToolJob. НЕ cancel activeTurn — пусть runTurn finally
     отработает.
   - runTurn обёрнут в try/finally: даже при CancellationException (от
     LiteConv.cancel()) и при early-return (interrupt до старта LLM) —
     finally закрывает LiteConv и эмитит Interrupted (если была отмена) + End.
   - runToolAndPersist возвращает WorkingMemoryEntry.ToolExchange вместо
     Pair(callId, resultText); инструмент запускается в scope.async, его
     Job = currentToolJob, cooperative cancellation через Job.cancel.
     Если инструмент броает CancellationException/InterruptedException →
     resultText = '[cancelled by user]', wasCancelled = true.

3. GetOrCreateLiteConversation теперь мапит ToolExchange →
   LiteMessage(TOOL, ToolResult, name, response) в initialMessages —
   при следующем send() LLM видит честный результат вызова tool'а
   через LiteRT-LM (callId не требуется, матчится по name).

4. LiteConv lifecycle: создаётся новый на каждом turn (close+recreate
   семантика). Это ~2s prefill на Gemma-4-E2B, но гарантирует полную
   предсказуемость: нет рекурсивных cancel-drain'ов, KV-cache всегда
   консистентен с WM.

5. Тесты:
   - multi-turn: 2 LiteConv-а (один на turn)
   - interrupt mid-slow-stream: пустой assistant в WM, только user, события
     Interrupted + End.
   - interrupt after-tool: ToolExchange в WM (result=echo output, wasCancelled=false),
     ToolCall + ToolResult в audit.

Total: 341/341 green.

storage-inmemory/src/commonTest/kotlin/pw/binom/agentik/storage/inmemory/InMemoryWorkingMemoryStoreTest.kt

@@ -15,21 +15,19 @@ class InMemoryWorkingMemoryStoreTest {
     fun `append assigns sequential order_idx starting from 0`() = runTest {
         val store = InMemoryWorkingMemoryStore()
         val t0 = Instant.parse("2026-09-15T10:00:00Z")
-        store.append("c1", WorkingMemoryEntry.System("you are brief"), t0)
         store.append("c1", WorkingMemoryEntry.User("u1", listOf(Content.Text("hi")), null), t0.plus(kotlin.time.Duration.parse("PT1S")))
         store.append("c1", WorkingMemoryEntry.Assistant("a1", listOf(Content.Text("hello"))), t0.plus(kotlin.time.Duration.parse("PT2S")))
         val rows = store.list("c1")
-        assertEquals(3, rows.size)
-        assertEquals(listOf(0L, 1L, 2L), rows.map { it.orderIdx })
+        assertEquals(2, rows.size)
+        assertEquals(listOf(0L, 1L), rows.map { it.orderIdx })
     }
 
     @Test
     fun `order_idx continues across conversations independently`() = runTest {
         val store = InMemoryWorkingMemoryStore()
         val t0 = Instant.parse("2026-09-15T10:00:00Z")
-        store.append("c1", WorkingMemoryEntry.System("a"), t0)
         store.append("c1", WorkingMemoryEntry.User("u1", listOf(Content.Text("hi")), null), t0)
-        store.append("c2", WorkingMemoryEntry.System("b"), t0)
+        store.append("c2", WorkingMemoryEntry.User("u2", listOf(Content.Text("hello")), null), t0)
         // c2 должен начать с 0, не продолжать c1
         val rows2 = store.list("c2")
         assertEquals(1, rows2.size)
@@ -56,8 +54,8 @@ class InMemoryWorkingMemoryStoreTest {
     fun `clear removes all rows for a conversation`() = runTest {
         val store = InMemoryWorkingMemoryStore()
         val t0 = Instant.parse("2026-09-15T10:00:00Z")
-        store.append("c1", WorkingMemoryEntry.System("a"), t0)
-        store.append("c2", WorkingMemoryEntry.System("b"), t0)
+        store.append("c1", WorkingMemoryEntry.User("u1", listOf(Content.Text("hi")), null), t0)
+        store.append("c2", WorkingMemoryEntry.User("u2", listOf(Content.Text("hello")), null), t0)
         store.clear("c1")
         assertEquals(emptyList(), store.list("c1"))
         assertEquals(1, store.list("c2").size)
@@ -67,23 +65,20 @@ class InMemoryWorkingMemoryStoreTest {
     fun `compact without summary drops tail and returns new max`() = runTest {
         val store = InMemoryWorkingMemoryStore()
         val t0 = Instant.parse("2026-09-15T10:00:00Z")
-        store.append("c1", WorkingMemoryEntry.System("a"), t0)
         store.append("c1", WorkingMemoryEntry.User("u1", listOf(Content.Text("hi")), null), t0.plus(kotlin.time.Duration.parse("PT1S")))
         store.append("c1", WorkingMemoryEntry.Assistant("a1", listOf(Content.Text("hello"))), t0.plus(kotlin.time.Duration.parse("PT2S")))
-        // dropFromOrderIdx=2 → удаляет всё >= 2 (то есть только Assistant "a1")
-        val newMax = store.compact(dropFromOrderIdx = 2, conversationId = "c1", summaryText = null)
-        assertEquals(1L, newMax)
+        // dropFromOrderIdx=1 → удаляет всё >= 1 (то есть только Assistant "a1")
+        val newMax = store.compact(dropFromOrderIdx = 1, conversationId = "c1", summaryText = null)
+        assertEquals(0L, newMax)
         val rows = store.list("c1")
-        assertEquals(2, rows.size)
-        assertEquals("a", (rows[0].entry as WorkingMemoryEntry.System).text)
-        assertEquals("u1", rows[1].entry.sourceMessageId)
+        assertEquals(1, rows.size)
+        assertEquals("u1", rows[0].entry.sourceMessageId)
     }
 
     @Test
     fun `compact with summary replaces tail with synthetic Summary row`() = runTest {
         val store = InMemoryWorkingMemoryStore()
         val t0 = Instant.parse("2026-09-15T10:00:00Z")
-        store.append("c1", WorkingMemoryEntry.System("you are brief"), t0)
         store.append("c1", WorkingMemoryEntry.User("u1", listOf(Content.Text("hi")), null), t0.plus(kotlin.time.Duration.parse("PT1S")))
         store.append("c1", WorkingMemoryEntry.Assistant("a1", listOf(Content.Text("hello"))), t0.plus(kotlin.time.Duration.parse("PT2S")))
         store.append("c1", WorkingMemoryEntry.User("u2", listOf(Content.Text("how are you")), null), t0.plus(kotlin.time.Duration.parse("PT3S")))