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

internal/ipc/client.go

@@ -69,6 +69,7 @@ var readOnlyMethods = map[Method]bool{
 	MethodLookupTool:           true,
 	MethodListTools:            true,
 	MethodListProposedRoutines: true,
+	MethodListTasks:            true,
 	MethodTickTrace:            true,
 	MethodMorningStatus:        true,
 	MethodDayPlan:              true,
@@ -427,6 +428,26 @@ func (c *Client) ListProposedRoutines(ctx context.Context) ([]ProposedRoutine, e
 	return r.Routines, nil
 }
 
+func (c *Client) CaptureTask(ctx context.Context, req CaptureTaskReq) (CaptureTaskResp, error) {
+	var r CaptureTaskResp
+	if err := c.call(ctx, MethodCaptureTask, req, &r); err != nil {
+		return CaptureTaskResp{}, err
+	}
+	return r, nil
+}
+
+func (c *Client) ListTasks(ctx context.Context, status string) ([]Task, error) {
+	var r listTasksResp
+	if err := c.call(ctx, MethodListTasks, listTasksReq{Status: status}, &r); err != nil {
+		return nil, err
+	}
+	return r.Tasks, nil
+}
+
+func (c *Client) SetTaskStatus(ctx context.Context, id int64, status string, ts time.Time) error {
+	return c.call(ctx, MethodSetTaskStatus, setTaskStatusReq{ID: id, Status: status, Ts: ts}, nil)
+}
+
 func (c *Client) DismissProposedRoutine(ctx context.Context, id int64) error {
 	return c.call(ctx, MethodDismissProposedRoutine, dismissProposedRoutineReq{ID: id}, nil)
 }