Push the week's plan to Google Calendar (Feature 16)

POST /api/v1/plans/{weekStart}/push-calendar writes one event per plan
day to the chosen calendar: "Dinner: {name}" from the household dinner
time for 60 minutes in the household zone, with the dinner name,
"Start by {time}" for crock-pot dinners and the
{MEALQUEST_PUBLIC_URL}/dinner/{id} link. Event ids are the lowercase
base32hex SHA-256 of "mealquest|{weekStart}|{date}"; each event is
inserted, and a 409 updates it instead.

gcal.Service.PushEvents does the Calendar writes under the account lock,
with the same redaction as listing. plan.Service.Push records a push only
when every event was written: the plan becomes synced with
calendar_synced_at and each day stores its event id. A partial failure
records nothing; a plan edited mid-push is 409 plan_changed.

A swap, or a redraft to another dinner, clears the day's
calendar_event_id, so the next push writes just those days; a push with
none pending writes every day again.

No calendar chosen is 409 no_calendar; a deleted or read-only chosen
calendar is 409 calendar_unavailable; a refused grant is 502
reconnect_required, leaving the connection as it is.

Maestro task 5885d2b1-cf06-44ff-abf3-242d7763c3c9.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/suggest/suggest_test.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"io"
 	"log/slog"
+	"net/url"
 	"slices"
 	"strings"
 	"sync"
@@ -19,6 +20,7 @@ import (
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/skills"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/db"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/dinners"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/gcal"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/household"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/jobs"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/plan"
@@ -927,7 +929,7 @@ func TestLaterBatchNeverResuggestsRenamedDrop(t *testing.T) {
 	fail := func(context.Context, string, skills.WeekRequest) (skills.Week, error) {
 		return skills.Week{}, errors.New("no draft in this test")
 	}
-	planSvc, err := plan.NewService(e.st, fail, e.runner, logger)
+	planSvc, err := plan.NewService(e.st, fail, e.runner, noCalendar{}, &url.URL{Scheme: "https", Host: "meals.example.com"}, logger)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1320,3 +1322,10 @@ func TestStartBatchRefusesUnknownTrigger(t *testing.T) {
 		t.Fatal("unknown trigger accepted")
 	}
 }
+
+// noCalendar is a plan.Calendar for tests that never push.
+type noCalendar struct{}
+
+func (noCalendar) PushEvents(context.Context, []gcal.Event) error {
+	return errors.New("no calendar in this test")
+}