Read spending from zenmoney in the poller, answer it from facts (#125)

The trust boundary is zenmoney, not maven — they already hold his bank
sessions. So the poller reads /v8/diff/ and writes totals as
facts(kind=env, source=poll:zenmoney); core reads those back when he asks
and never sees the token.

internal/zenmoney sums transactions per currency over a window, skipping
tombstoned rows and transfers between his own accounts, and refuses to
encode a summary built from zero transactions. That refusal is the whole
design: a failed or empty read writes nothing and leaves the last good
total alone, because a zero recited as fact is worse than silence. No
currency conversion either — a figure he can check against his bank beats
one he cannot.

Off unless configured, and the token is read from a FILE rather than a
flag so it never lands in `ps`, in docker-compose.yml, or in shell
history. Nothing about the money is search input, no tick rule reads the
keys, and the log lines name keys, never figures.

The live-credential half is BLOCKED: there is no zenmoney account or token
here, so everything is verified against a recorded diff fixture.

cmd/mavend/actions_money_test.go

@@ -0,0 +1,139 @@
+package main
+
+import (
+	"context"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/kami/maven/internal/ipc"
+	"github.com/kami/maven/internal/router"
+	"github.com/kami/maven/internal/zenmoney"
+)
+
+// moneyAPI answers only LatestFactBySource; everything else is unimplemented,
+// which is the assertion that answering a money question costs no model call
+// and reaches no network.
+type moneyAPI struct {
+	ipc.UnimplementedCoreAPI
+
+	fact    ipc.Fact
+	err     error
+	gotKey  string
+	gotSrc  string
+	callCnt int
+}
+
+func (a *moneyAPI) LatestFactBySource(_ context.Context, key, source string) (ipc.Fact, error) {
+	a.gotKey, a.gotSrc = key, source
+	a.callCnt++
+	return a.fact, a.err
+}
+
+func moneyNow() time.Time { return time.Date(2026, 8, 15, 20, 0, 0, 0, time.UTC) }
+
+func moneyFact(ts time.Time, val string) ipc.Fact {
+	return ipc.Fact{Kind: "env", Key: zenmoney.KeySpentMonth, Value: val, Source: zenmoney.Source, Ts: ts}
+}
+
+func TestQueryMoneyAnswersFromTheFact(t *testing.T) {
+	api := &moneyAPI{fact: moneyFact(moneyNow(), `{"spent":[{"currency":"RUB","amount":1749.5}],"count":3}`)}
+	h := &reactiveHandler{api: api, now: moneyNow}
+	reply, ok := h.queryMoney(context.Background(), &queryTurn{
+		dec: router.Decision{Utterance: "сколько я потратил в этом месяце?"},
+	})
+	if !ok {
+		t.Fatal("the money source must claim a money question")
+	}
+	if api.gotKey != zenmoney.KeySpentMonth || api.gotSrc != zenmoney.Source {
+		t.Errorf("read %q/%q, want the month key from the poller's source", api.gotKey, api.gotSrc)
+	}
+	if !strings.Contains(reply, "1749.5") {
+		t.Errorf("reply = %q, want the exact figure", reply)
+	}
+	if !strings.Contains(reply, "в этом месяце") {
+		t.Errorf("reply = %q, want the window named", reply)
+	}
+}
+
+func TestQueryMoneyPicksTodaysKey(t *testing.T) {
+	api := &moneyAPI{fact: moneyFact(moneyNow(), `{"spent":[{"currency":"RUB","amount":250}],"count":1}`)}
+	h := &reactiveHandler{api: api, now: moneyNow}
+	if _, ok := h.queryMoney(context.Background(), &queryTurn{
+		dec: router.Decision{Utterance: "сколько я потратил сегодня?"},
+	}); !ok {
+		t.Fatal("expected the source to claim it")
+	}
+	if api.gotKey != zenmoney.KeySpentToday {
+		t.Errorf("key = %q, want today's", api.gotKey)
+	}
+}
+
+// The capability is off unless configured, and then there is no fact. She says
+// so instead of letting the recall pass answer a money question from a note.
+func TestQueryMoneySaysNotConnected(t *testing.T) {
+	h := &reactiveHandler{api: &moneyAPI{err: ipc.ErrNoFact}, now: moneyNow}
+	reply, ok := h.queryMoney(context.Background(), &queryTurn{
+		dec: router.Decision{Utterance: "сколько я потратил?"},
+	})
+	if !ok {
+		t.Fatal("expected the source to claim it")
+	}
+	if !strings.Contains(reply, "не подключено") {
+		t.Errorf("reply = %q, want an honest 'not connected'", reply)
+	}
+	// No number of any kind in that answer.
+	for _, d := range []string{"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"} {
+		if strings.Contains(reply, d) {
+			t.Errorf("reply %q contains a digit — nothing was read, so there is no figure", reply)
+		}
+	}
+}
+
+// A fact older than the staleness bound is dated rather than spoken as if it
+// were current: the poller can be down, and last week's total presented as
+// today's is a lie by omission.
+func TestQueryMoneyDatesAStaleFact(t *testing.T) {
+	old := moneyNow().Add(-72 * time.Hour)
+	api := &moneyAPI{fact: moneyFact(old, `{"spent":[{"currency":"RUB","amount":100}],"count":1}`)}
+	h := &reactiveHandler{api: api, now: moneyNow}
+	reply, _ := h.queryMoney(context.Background(), &queryTurn{
+		dec: router.Decision{Utterance: "сколько я потратил?"},
+	})
+	if !strings.Contains(reply, "данные от") {
+		t.Errorf("reply = %q, want the stale fact dated", reply)
+	}
+}
+
+func TestQueryMoneyPassesOtherQuestions(t *testing.T) {
+	api := &moneyAPI{}
+	h := &reactiveHandler{api: api, now: moneyNow}
+	for _, u := range []string{"какая погода?", "я потратил весь день на это", "какие у меня задачи?"} {
+		if _, ok := h.queryMoney(context.Background(), &queryTurn{dec: router.Decision{Utterance: u}}); ok {
+			t.Errorf("the money source claimed %q", u)
+		}
+	}
+	if api.callCnt != 0 {
+		t.Error("a non-money question must not read the money facts")
+	}
+}
+
+// Money must be answered before the recall sources, or a question about
+// spending gets answered by the nearest note.
+func TestQuerySourcesOrderMoneyBeforeRecall(t *testing.T) {
+	moneyAt, notesAt := -1, -1
+	for i, src := range querySources {
+		switch src.name {
+		case "money":
+			moneyAt = i
+		case "notes":
+			notesAt = i
+		}
+	}
+	if moneyAt < 0 || notesAt < 0 {
+		t.Fatalf("sources missing: money=%d notes=%d", moneyAt, notesAt)
+	}
+	if moneyAt > notesAt {
+		t.Errorf("money source at %d, after notes at %d", moneyAt, notesAt)
+	}
+}