Capture tasks, with one intake seam mail can call later (#130)

A task is not a fact and not a note. A fact is a claim about the world that a
correction supersedes; a note is something to recall by meaning. A task is work
with a lifecycle, and the read that matters is "everything outstanding right
now" — which over an append-only log would mean replaying history on every
question. So: a tasks table, migration #14, statuses candidate/open/done/dropped
that each move forward exactly once.

Dedupe is on normalised text among LIVE rows only, via a partial unique index.
That is the property the mail side needs: an extractor may call CaptureTask for
every message it reads, as often as it likes, without growing the list — while a
weekly errand is still capturable again once the last one is done.

Three ways in, one seam. ipc.CaptureTaskReq is it: the voice path
(router.ParseTaskCapture on an explicit marker — "добавь в задачи …", never
"надо бы поспать"), the /tasks form, and the email reader from #246 when it
exists. Mail-derived items set Source "email:<account>", Status "candidate" and
Evidence to whatever makes the row reviewable; a candidate is inert until he
confirms it on /tasks, and Maven names it as unconfirmed when she recites the
list rather than putting words in his mouth.

No new intent — the router enum is a contract with the relabelling prompt, so
capture rides the note intent and the list rides a query source, both matched
deterministically like the calendar and plan matchers already are.

Nothing here speaks. No tick rule reads tasks; the list is answered when asked
about, which is why /tasks POST is not step-up gated the way /tools and
/routines are — a task write moves no boundary.

Vikunja #130

cmd/mavend/actions_task.go

@@ -0,0 +1,99 @@
+package main
+
+import (
+	"context"
+	"log"
+	"strings"
+
+	"github.com/kami/maven/internal/ipc"
+	"github.com/kami/maven/internal/router"
+	"github.com/kami/maven/internal/store"
+)
+
+// Task capture on the voice/chat path (Vikunja #130).
+//
+// Two halves, both deliberately small:
+//
+//   - captureTaskFromNote runs at the top of actionNote. An utterance that
+//     explicitly files a task ("добавь в задачи купить молоко") goes to the task
+//     store instead of the note store. Anything without an explicit marker is
+//     still a note — see router.ParseTaskCapture for why "надо бы поспать" must
+//     not become a task.
+//   - queryTasks is a query source that reads the list back.
+//
+// Nothing here speaks unprompted. Tasks are answered when asked about; no tick
+// rule reads the table.
+
+// captureTaskFromNote claims the turn when the utterance explicitly files a
+// task, returning the reply. ("", false) hands the turn back to the note path.
+func (h *reactiveHandler) captureTaskFromNote(ctx context.Context, dec router.Decision) (string, bool) {
+	text, ok := router.ParseTaskCapture(dec.Utterance)
+	if !ok {
+		return "", false
+	}
+	resp, err := h.api.CaptureTask(ctx, ipc.CaptureTaskReq{
+		Text:   text,
+		Source: "tap:voice",
+		Status: store.TaskOpen, // he stated it himself — not a candidate
+		Ts:     h.now(),
+	})
+	if err != nil {
+		log.Printf("voice: capture task: %v", err)
+		return "не получилось записать задачу.", true
+	}
+	if !resp.Created {
+		return "это уже в списке.", true
+	}
+	return "записала: " + text, true
+}
+
+// queryTasks — "какие у меня задачи?", "что мне нужно сделать?".
+//
+// Reads the live set and recites it. Newest first, which is the order the store
+// returns: this source has no opinion about which task matters more, and
+// pretending otherwise would be a guess. Ranking is Vikunja #129.
+func (h *reactiveHandler) queryTasks(ctx context.Context, t *queryTurn) (string, bool) {
+	if !router.IsTaskListQuery(t.dec.Utterance) {
+		return "", false
+	}
+	tasks, err := h.api.ListTasks(ctx, "live")
+	if err != nil {
+		log.Printf("voice: list tasks: %v", err)
+		return "не получилось посмотреть задачи.", true
+	}
+	return formatTaskListRU(tasks), true
+}
+
+// formatTaskListRU renders the live task list the way Maven says it. Candidates
+// are named as candidates — a task she pulled out of his mail is something she
+// suggests, and saying it in the same breath as work he actually stated would
+// put words in his mouth.
+func formatTaskListRU(tasks []ipc.Task) string {
+	var open, cands []string
+	for _, t := range tasks {
+		switch t.Status {
+		case store.TaskCandidate:
+			cands = append(cands, t.Text)
+		default:
+			open = append(open, t.Text)
+		}
+	}
+	if len(open) == 0 && len(cands) == 0 {
+		return "задач нет."
+	}
+	var b strings.Builder
+	if len(open) > 0 {
+		b.WriteString("в списке: ")
+		b.WriteString(strings.Join(open, "; "))
+		b.WriteString(".")
+	}
+	if len(cands) > 0 {
+		if b.Len() > 0 {
+			b.WriteString(" ")
+		}
+		b.WriteString("ещё я нашла, но ты не подтвердил: ")
+		b.WriteString(strings.Join(cands, "; "))
+		b.WriteString(".")
+	}
+	return b.String()
+}