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.

internal/router/task_test.go

@@ -20,6 +20,17 @@ func TestParseTaskCapture(t *testing.T) {
 		{"новая задача важно позвонить маме", "позвонить маме", 2, true},
 		// The stem inside the task text is part of the task, not a marker.
 		{"добавь в задачи позвонить в срочную помощь", "позвонить в срочную помощь", 0, true},
+		// Whisper punctuates dictated Russian. The marker used to be missed as
+		// soon as anything sat next to it, and then it stayed in the task text
+		// and in the dedupe key — the exact task he was trying to flag.
+		{"добавь в задачи оплатить интернет, срочно", "оплатить интернет", 3, true},
+		{"добавь в задачи очень срочно оплатить интернет", "оплатить интернет", 3, true},
+		{"добавь в задачи оплатить интернет — важно", "оплатить интернет", 2, true},
+		// A dictated question mark is not part of the task.
+		{"добавь в задачи позвонить в банк?", "позвонить в банк", 0, true},
+		// The phrasings he uses that the prefix list did not have.
+		{"поставь задачу вынести мусор", "вынести мусор", 0, true},
+		{"добавь в тудушки купить лампочки", "купить лампочки", 0, true},
 		// A marker with nothing after it files nothing.
 		{"добавь в задачи", "", 0, false},
 		{"новая задача", "", 0, false},
@@ -47,6 +58,7 @@ func TestIsTaskListQuery(t *testing.T) {
 		"задачи",
 		"мои задачи",
 		"what should I do",
+		"что мне делать?",
 	}
 	for _, s := range yes {
 		if !IsTaskListQuery(s) {
@@ -55,6 +67,13 @@ func TestIsTaskListQuery(t *testing.T) {
 	}
 	no := []string{
 		"как дела?",
+		// No task noun and no pronoun: these fired ahead of recall and the
+		// model, and answered a question about a file or a server with
+		// "задач нет."
+		"что нужно сделать чтобы перезапустить сервер?",
+		"что мне сделать с этим файлом?",
+		"what does docker do?",
+		"what do you do?",
 		"какая погода?",
 		"напомни мне позвонить маме в шесть",
 		"я сделал зарядку",