fix(services): add db tags to SummaryCounts so sqlx maps this_week (et al.)

Bug 1 (smoke-auth-2026-04-25.md) had a third symptom beyond the RLS
function bodies and the visibilityPredicate `::uuid[]` issue:
/api/deadlines/summary and /api/appointments/summary returned 500 with
`sqlx: missing destination name this_week in *services.SummaryCounts`.

Cause: SummaryCounts (deadline) and AppointmentSummaryCounts had only
`json:` tags. sqlx falls back to the lower-cased field name when no `db:`
tag is present, so `ThisWeek` mapped to `thisweek` — but the SQL aliases
the column as `AS this_week`. Adding `db:"this_week"` (and matching tags
for the other fields) lets sqlx find the destination.

Verified by hitting both endpoints; previously 500 → now expected 200.

internal/services/appointment_service.go

@@ -404,10 +404,10 @@ func (s *AppointmentService) Delete(ctx context.Context, userID, terminID uuid.U
 
 // AppointmentSummaryCounts buckets visible Appointments into today / this_week / later.
 type AppointmentSummaryCounts struct {
-	Today    int `json:"today"`
-	ThisWeek int `json:"this_week"`
-	Later    int `json:"later"`
-	Total    int `json:"total"`
+	Today    int `json:"today"     db:"today"`
+	ThisWeek int `json:"this_week" db:"this_week"`
+	Later    int `json:"later"     db:"later"`
+	Total    int `json:"total"     db:"total"`
 }
 
 // SummaryCounts aggregates Appointments by start-date bucket for the user's visible projects.

internal/services/deadline_service.go

@@ -383,11 +383,11 @@ func (s *DeadlineService) Delete(ctx context.Context, userID, fristID uuid.UUID)
 
 // SummaryCounts returns traffic-light counts across the user's visible Deadlines.
 type SummaryCounts struct {
-	Overdue   int `json:"overdue"`
-	ThisWeek  int `json:"this_week"`
-	Upcoming  int `json:"upcoming"`
-	Completed int `json:"completed"`
-	Total     int `json:"total"`
+	Overdue   int `json:"overdue"   db:"overdue"`
+	ThisWeek  int `json:"this_week" db:"this_week"`
+	Upcoming  int `json:"upcoming"  db:"upcoming"`
+	Completed int `json:"completed" db:"completed"`
+	Total     int `json:"total"     db:"total"`
 }
 
 // SummaryCounts aggregates Deadlines by due-date bucket for the user's visible