Keep tool group keys unique across transcript

app/androidApp/src/test/kotlin/com/example/aiapp/ToolRowsTest.kt

@@ -111,6 +111,27 @@ class ToolRowsTest {
         assertEquals("b", rows.first().key)
     }
 
+    @Test
+    fun a_run_that_reappears_after_another_row_keeps_distinct_keys() {
+        val rows =
+            groupToolRuns(
+                listOf(
+                    call("older", runId = "exec-1"),
+                    call("older-2", runId = "exec-1"),
+                    reply(),
+                    call("exec-1", runId = "exec-1"),
+                    call("newer", runId = "exec-1"),
+                    reply(),
+                )
+            )
+
+        assertTrue(rows[0] is TranscriptRow.Tools, "$rows")
+        assertTrue(rows[2] is TranscriptRow.Tools, "$rows")
+        assertKeysDistinct(rows)
+        assertEquals("exec-1", rows[0].key)
+        assertEquals("exec-1/exec-1", rows[2].key)
+    }
+
     /**
      * Finishing is not what folds a call back in -- being overtaken is. A session that has run its
      * last command and is writing its reply leaves that command standing until the reply starts.