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/db/querier.go

@@ -176,6 +176,10 @@ type Querier interface {
 	// Records an edit of plan id, raising its revision: a synced plan becomes
 	// changed, any other keeps its status.
 	MarkWeekPlanEdited(ctx context.Context, arg MarkWeekPlanEditedParams) error
+	// Records a Push to Calendar of plan id as it was at revision: the plan
+	// becomes synced. A plan edited since (another revision) is left as it is
+	// (0 rows).
+	MarkWeekPlanSynced(ctx context.Context, arg MarkWeekPlanSyncedParams) (int64, error)
 	// Moves a dinner still suggested to status (quest_log or archived),
 	// recording updated_by; a dinner no longer suggested is left as it is
 	// (0 rows).
@@ -186,8 +190,9 @@ type Querier interface {
 	MoveTriedDinner(ctx context.Context, arg MoveTriedDinnerParams) (int64, error)
 	// Stores a partial result of a running job.
 	PublishJobResult(ctx context.Context, arg PublishJobResultParams) (int64, error)
-	// Plans dinner_id on date of plan_id, keeping the day's calendar event id
-	// when the day exists.
+	// Plans dinner_id on date of plan_id. An existing day keeps its calendar
+	// event id while its dinner stays the same; a new dinner clears it, since
+	// Calendar no longer shows the day as planned.
 	PutPlanDay(ctx context.Context, arg PutPlanDayParams) error
 	// Records a new draft over plan id: its status and note, raising its
 	// revision.
@@ -196,12 +201,16 @@ type Querier interface {
 	SetDinnerFavorite(ctx context.Context, arg SetDinnerFavoriteParams) (Dinner, error)
 	// Sets the chosen calendar; affects no row when nothing is connected.
 	SetIntegrationsGoogleCalendar(ctx context.Context, arg SetIntegrationsGoogleCalendarParams) (int64, error)
+	// Records that the event calendar_event_id on Calendar shows date of
+	// plan_id as planned.
+	SetPlanDayCalendarEvent(ctx context.Context, arg SetPlanDayCalendarEventParams) (int64, error)
 	// Marks a pending batch running; a batch in any other status is left as
 	// it is (0 rows).
 	StartSuggestionBatch(ctx context.Context, arg StartSuggestionBatchParams) (int64, error)
 	SucceedJob(ctx context.Context, arg SucceedJobParams) (int64, error)
-	// Plans dinner_id on an existing day of plan_id; a date the plan does not
-	// have is left as it is (0 rows).
+	// Plans dinner_id on an existing day of plan_id, clearing its calendar
+	// event id since Calendar no longer shows the day as planned; a date the
+	// plan does not have is left as it is (0 rows).
 	SwapPlanDay(ctx context.Context, arg SwapPlanDayParams) (int64, error)
 	// An unknown id returns sql.ErrNoRows.
 	ToggleDinnerFavorite(ctx context.Context, arg ToggleDinnerFavoriteParams) (Dinner, error)