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/plans.sql.go

@@ -154,7 +154,7 @@ func (q *Queries) ListDraftPool(ctx context.Context, arg ListDraftPoolParams) ([
 }
 
 const listPlanDays = `-- name: ListPlanDays :many
-SELECT plan_days.date, plan_days.is_new, dinners.id, dinners.name, dinners.normalized_name, dinners.status, dinners.origin, dinners.method, dinners.minutes_total, dinners.difficulty, dinners.cuisine, dinners.is_favorite, dinners.recipe_id, dinners.photo_id, dinners.grounding_status, dinners.updated_by, dinners.created_at, dinners.updated_at, dinners.recipe_url, dinners.grounding_error, dinners.grounding_revision
+SELECT plan_days.date, plan_days.is_new, plan_days.calendar_event_id, dinners.id, dinners.name, dinners.normalized_name, dinners.status, dinners.origin, dinners.method, dinners.minutes_total, dinners.difficulty, dinners.cuisine, dinners.is_favorite, dinners.recipe_id, dinners.photo_id, dinners.grounding_status, dinners.updated_by, dinners.created_at, dinners.updated_at, dinners.recipe_url, dinners.grounding_error, dinners.grounding_revision
 FROM plan_days
 JOIN dinners ON dinners.id = plan_days.dinner_id
 WHERE plan_days.plan_id = ?
@@ -162,9 +162,10 @@ ORDER BY plan_days.date
 `
 
 type ListPlanDaysRow struct {
-	Date   string
-	IsNew  int64
-	Dinner Dinner
+	Date            string
+	IsNew           int64
+	CalendarEventID sql.NullString
+	Dinner          Dinner
 }
 
 // The days of plan plan_id with their dinners, Monday first. A day with
@@ -181,6 +182,7 @@ func (q *Queries) ListPlanDays(ctx context.Context, planID string) ([]ListPlanDa
 		if err := rows.Scan(
 			&i.Date,
 			&i.IsNew,
+			&i.CalendarEventID,
 			&i.Dinner.ID,
 			&i.Dinner.Name,
 			&i.Dinner.NormalizedName,
@@ -267,11 +269,42 @@ func (q *Queries) MarkWeekPlanEdited(ctx context.Context, arg MarkWeekPlanEdited
 	return err
 }
 
+const markWeekPlanSynced = `-- name: MarkWeekPlanSynced :execrows
+UPDATE week_plans
+SET status = 'synced', calendar_synced_at = ?, updated_at = ?
+WHERE id = ? AND revision = ?
+`
+
+type MarkWeekPlanSyncedParams struct {
+	CalendarSyncedAt sql.NullString
+	UpdatedAt        string
+	ID               string
+	Revision         int64
+}
+
+// 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).
+func (q *Queries) MarkWeekPlanSynced(ctx context.Context, arg MarkWeekPlanSyncedParams) (int64, error) {
+	result, err := q.db.ExecContext(ctx, markWeekPlanSynced,
+		arg.CalendarSyncedAt,
+		arg.UpdatedAt,
+		arg.ID,
+		arg.Revision,
+	)
+	if err != nil {
+		return 0, err
+	}
+	return result.RowsAffected()
+}
+
 const putPlanDay = `-- name: PutPlanDay :exec
 INSERT INTO plan_days (id, plan_id, date, dinner_id, is_new, created_at, updated_at)
 VALUES (?, ?, ?, ?, ?, ?, ?)
 ON CONFLICT (plan_id, date) DO UPDATE
-SET dinner_id = excluded.dinner_id, is_new = excluded.is_new, updated_at = excluded.updated_at
+SET dinner_id = excluded.dinner_id, is_new = excluded.is_new,
+	calendar_event_id = CASE WHEN plan_days.dinner_id IS excluded.dinner_id THEN plan_days.calendar_event_id END,
+	updated_at = excluded.updated_at
 `
 
 type PutPlanDayParams struct {
@@ -284,8 +317,9 @@ type PutPlanDayParams struct {
 	UpdatedAt string
 }
 
-// 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.
 func (q *Queries) PutPlanDay(ctx context.Context, arg PutPlanDayParams) error {
 	_, err := q.db.ExecContext(ctx, putPlanDay,
 		arg.ID,
@@ -324,9 +358,37 @@ func (q *Queries) RedraftWeekPlan(ctx context.Context, arg RedraftWeekPlanParams
 	return err
 }
 
+const setPlanDayCalendarEvent = `-- name: SetPlanDayCalendarEvent :execrows
+UPDATE plan_days
+SET calendar_event_id = ?, updated_at = ?
+WHERE plan_id = ? AND date = ?
+`
+
+type SetPlanDayCalendarEventParams struct {
+	CalendarEventID sql.NullString
+	UpdatedAt       string
+	PlanID          string
+	Date            string
+}
+
+// Records that the event calendar_event_id on Calendar shows date of
+// plan_id as planned.
+func (q *Queries) SetPlanDayCalendarEvent(ctx context.Context, arg SetPlanDayCalendarEventParams) (int64, error) {
+	result, err := q.db.ExecContext(ctx, setPlanDayCalendarEvent,
+		arg.CalendarEventID,
+		arg.UpdatedAt,
+		arg.PlanID,
+		arg.Date,
+	)
+	if err != nil {
+		return 0, err
+	}
+	return result.RowsAffected()
+}
+
 const swapPlanDay = `-- name: SwapPlanDay :execrows
 UPDATE plan_days
-SET dinner_id = ?, is_new = ?, updated_at = ?
+SET dinner_id = ?, is_new = ?, calendar_event_id = NULL, updated_at = ?
 WHERE plan_id = ? AND date = ?
 `
 
@@ -338,8 +400,9 @@ type SwapPlanDayParams struct {
 	Date      string
 }
 
-// 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).
 func (q *Queries) SwapPlanDay(ctx context.Context, arg SwapPlanDayParams) (int64, error) {
 	result, err := q.db.ExecContext(ctx, swapPlanDay,
 		arg.DinnerID,