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/server.go

@@ -231,6 +231,48 @@ func (a *storeAPI) DeleteTool(ctx context.Context, name string) error {
 	return mapErr(a.s.DeleteTool(ctx, name))
 }
 
+func (a *storeAPI) CaptureTask(ctx context.Context, req CaptureTaskReq) (CaptureTaskResp, error) {
+	id, created, err := a.s.CaptureTask(ctx, store.Task{
+		CreatedTs: req.Ts,
+		Text:      req.Text,
+		Source:    req.Source,
+		Evidence:  req.Evidence,
+		Status:    req.Status,
+		Due:       req.Due,
+		Weight:    req.Weight,
+	})
+	if err != nil {
+		return CaptureTaskResp{}, mapErr(err)
+	}
+	return CaptureTaskResp{ID: id, Created: created}, nil
+}
+
+func (a *storeAPI) ListTasks(ctx context.Context, status string) ([]Task, error) {
+	ts, err := a.s.ListTasks(ctx, status)
+	if err != nil {
+		return nil, mapErr(err)
+	}
+	out := make([]Task, len(ts))
+	for i, t := range ts {
+		out[i] = Task{
+			ID:        t.ID,
+			CreatedTs: t.CreatedTs,
+			Text:      t.Text,
+			Source:    t.Source,
+			Evidence:  t.Evidence,
+			Status:    t.Status,
+			Due:       t.Due,
+			Weight:    t.Weight,
+			Resolved:  t.ResolvedTs,
+		}
+	}
+	return out, nil
+}
+
+func (a *storeAPI) SetTaskStatus(ctx context.Context, id int64, status string, ts time.Time) error {
+	return mapErr(a.s.SetTaskStatus(ctx, id, status, ts))
+}
+
 func (a *storeAPI) ListProposedRoutines(ctx context.Context) ([]ProposedRoutine, error) {
 	rs, err := a.s.ListProposedRoutines(ctx)
 	if err != nil {
@@ -700,6 +742,22 @@ var methodTable = map[Method]handlerFunc{
 	MethodDeleteTool: withParamsVoid(func(ctx context.Context, api CoreAPI, p disableToolReq) error {
 		return api.DeleteTool(ctx, p.Name)
 	}),
+	MethodCaptureTask: withParams(func(ctx context.Context, api CoreAPI, p CaptureTaskReq) (CaptureTaskResp, error) {
+		return api.CaptureTask(ctx, p)
+	}),
+	MethodListTasks: withParams(func(ctx context.Context, api CoreAPI, p listTasksReq) (listTasksResp, error) {
+		out, err := api.ListTasks(ctx, p.Status)
+		if err != nil {
+			return listTasksResp{}, err
+		}
+		if out == nil {
+			out = []Task{}
+		}
+		return listTasksResp{Tasks: out}, nil
+	}),
+	MethodSetTaskStatus: withParamsVoid(func(ctx context.Context, api CoreAPI, p setTaskStatusReq) error {
+		return api.SetTaskStatus(ctx, p.ID, p.Status, p.Ts)
+	}),
 	MethodListProposedRoutines: withoutParams(func(ctx context.Context, api CoreAPI) (listProposedRoutinesResp, error) {
 		out, err := api.ListProposedRoutines(ctx)
 		if err != nil {