tasks: key derived captures by external id and record who resolved

A task extracted from mail deduped on the live-norm index only, so once he
finished it the row left the live set and the next poll of the same immutable
message re-extracted it as a fresh candidate. mavmaild is a read-only reader
and marks nothing read, so that repeats forever. Derived rows now carry an
ext_id built from the message uid and the extracted span, unique across every
status, while voice keeps live-only norm dedupe because saying an errand again
is the recurrence signal. A derived source can no longer capture straight to
open, and saying a task out loud that Maven had only proposed promotes the
candidate instead of answering that it is already in the list.

SetTaskStatus was classified AuthRead. Resolving a task is not additive, it
erases work off his list, so it is a write, and the row now records the caller
that moved it. ListTasks was unbounded. The list-query matcher claimed any
utterance with "что мне делать", including "с чем мне помочь", and the urgency
stripper matched inside words.

Found in review of #60.

cmd/mavend/actions_task_test.go

@@ -19,6 +19,7 @@ type taskAPI struct {
 
 	captured []ipc.CaptureTaskReq
 	created  bool
+	promoted bool
 	capErr   error
 
 	tasks   []ipc.Task
@@ -31,7 +32,7 @@ func (a *taskAPI) CaptureTask(_ context.Context, req ipc.CaptureTaskReq) (ipc.Ca
 	if a.capErr != nil {
 		return ipc.CaptureTaskResp{}, a.capErr
 	}
-	return ipc.CaptureTaskResp{ID: 1, Created: a.created}, nil
+	return ipc.CaptureTaskResp{ID: 1, Created: a.created, Promoted: a.promoted}, nil
 }
 
 func (a *taskAPI) ListTasks(_ context.Context, status string) ([]ipc.Task, error) {
@@ -225,3 +226,29 @@ func TestQuerySourcesOrderTasksBeforeRecall(t *testing.T) {
 		t.Errorf("tasks source at %d, after notes at %d", tasksAt, notesAt)
 	}
 }
+
+// Saying a task out loud that Maven had only proposed is a confirmation. She
+// used to answer "это уже в списке" and then read it back, in the same
+// conversation, as something he had not confirmed.
+func TestCaptureTaskFromNoteAcknowledgesAPromotion(t *testing.T) {
+	api := &taskAPI{promoted: true}
+	h := taskHandler(api)
+	reply, ok := h.captureTaskFromNote(context.Background(), router.Decision{
+		Intent: router.IntentNote, Utterance: "добавь в задачи продлить страховку",
+	})
+	if !ok {
+		t.Fatal("an explicit capture must claim the turn")
+	}
+	if strings.Contains(reply, "уже в списке") {
+		t.Errorf("reply = %q — he just confirmed it, that is not a duplicate", reply)
+	}
+	if !strings.Contains(reply, "продлить страховку") {
+		t.Errorf("reply = %q, want the task named back", reply)
+	}
+	// Persona: feminine, informal.
+	for _, bad := range []string{"рад ", "вы ", "ваш"} {
+		if strings.Contains(reply, bad) {
+			t.Errorf("reply %q contains %q", reply, bad)
+		}
+	}
+}