Fix stale Regular grounding and enforce three Regulars for onboarding

A background grounding result now applies only while the dinner is still
pending under the normalized name the job searched: GroundPendingDinner and
FailPendingDinnerGrounding match normalized_name, so a rename makes the old
job's success or failure a no-op. Renaming a dinner still pending enqueues
a fresh grounding job for the new name; if that cannot be enqueued, the
dinner's grounding is failed so it is not left pending with no job.

Completing onboarding (PATCH /api/v1/settings/household with
onboarding_completed true) is refused with 400 invalid_settings until the
household has at least three Regulars (status regular; archived and Quest
log dinners do not count), and onboarding_completed_at is set only then.

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

internal/household/settings.go

@@ -71,10 +71,15 @@ type SettingsPatch struct {
 	// OnboardingCompleted, when true, records that the household finished
 	// onboarding: onboarding_completed_at becomes the time of the update,
 	// unless it is already set, when the first time is kept. Onboarding is
-	// never undone, so false is invalid.
+	// never undone, so false is invalid, and it cannot first be completed
+	// with fewer than MinRegulars Regulars.
 	OnboardingCompleted *bool
 }
 
+// MinRegulars is how many Regulars the household must have to complete
+// onboarding.
+const MinRegulars = 3
+
 // Problem is one invalid field of a SettingsPatch, named by its JSON key.
 type Problem struct {
 	Field  string
@@ -167,7 +172,8 @@ func (s *SettingsService) Get(ctx context.Context) (Settings, error) {
 // Update validates patch, applies it, records updatedBy (the signed-in
 // member's subject, which must not be empty) and publishes the new settings
 // to every subscriber. An invalid patch is a *ValidationError and changes
-// nothing.
+// nothing, as does completing onboarding with fewer than MinRegulars
+// Regulars.
 func (s *SettingsService) Update(ctx context.Context, patch SettingsPatch, updatedBy string) (Settings, error) {
 	if updatedBy == "" {
 		return Settings{}, errors.New("household: update settings: no member to record as updated_by")
@@ -214,6 +220,16 @@ func (s *SettingsService) Update(ctx context.Context, patch SettingsPatch, updat
 		setDow(&p.ChatAutosendDow, patch.ChatAutosendDow)
 		setString(&p.ChatAutosendTime, patch.ChatAutosendTime)
 		if patch.OnboardingCompleted != nil && !p.OnboardingCompletedAt.Valid {
+			n, err := q.CountRegularDinners(ctx)
+			if err != nil {
+				return fmt.Errorf("household: count Regulars: %w", err)
+			}
+			if n < MinRegulars {
+				return &ValidationError{Problems: []Problem{{
+					Field:  "onboarding_completed",
+					Reason: fmt.Sprintf("add at least %d Regulars first (have %d)", MinRegulars, n),
+				}}}
+			}
 			p.OnboardingCompletedAt = sql.NullString{String: p.UpdatedAt, Valid: true}
 		}
 		row, err = q.UpsertHouseholdSettings(ctx, p)