Fix time-off date display and improve UI

Scan datetime columns directly into time.Time instead of strings in the
timeoff store — the intermediate string parse silently failed with
parseTime=true, producing zero-value dates. Display dates with month
names and filter admin's own entry from the volunteer dropdown.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/timeoff/timeoff.go

@@ -80,25 +80,20 @@ func (s *Store) Create(ctx context.Context, volunteerID int64, in CreateInput) (
 
 func (s *Store) GetByID(ctx context.Context, id int64) (*Request, error) {
 	req := &Request{}
-	var startsAt, endsAt, createdAt, updatedAt string
 	var reason sql.NullString
 	var reviewedBy sql.NullInt64
-	var reviewedAt sql.NullString
+	var reviewedAt sql.NullTime
 
 	err := s.db.QueryRowContext(ctx,
 		`SELECT id, volunteer_id, starts_at, ends_at, reason, status, reviewed_by, reviewed_at, created_at, updated_at
 		 FROM time_off_requests WHERE id = ?`, id,
-	).Scan(&req.ID, &req.VolunteerID, &startsAt, &endsAt, &reason, &req.Status, &reviewedBy, &reviewedAt, &createdAt, &updatedAt)
+	).Scan(&req.ID, &req.VolunteerID, &req.StartsAt, &req.EndsAt, &reason, &req.Status, &reviewedBy, &reviewedAt, &req.CreatedAt, &req.UpdatedAt)
 	if errors.Is(err, sql.ErrNoRows) {
 		return nil, ErrNotFound
 	}
 	if err != nil {
 		return nil, fmt.Errorf("get time off request: %w", err)
 	}
-	req.StartsAt, _ = time.Parse("2006-01-02 15:04:05", startsAt)
-	req.EndsAt, _ = time.Parse("2006-01-02 15:04:05", endsAt)
-	req.CreatedAt, _ = time.Parse("2006-01-02 15:04:05", createdAt)
-	req.UpdatedAt, _ = time.Parse("2006-01-02 15:04:05", updatedAt)
 	if reason.Valid {
 		req.Reason = reason.String
 	}
@@ -106,8 +101,7 @@ func (s *Store) GetByID(ctx context.Context, id int64) (*Request, error) {
 		req.ReviewedBy = &reviewedBy.Int64
 	}
 	if reviewedAt.Valid {
-		t, _ := time.Parse("2006-01-02 15:04:05", reviewedAt.String)
-		req.ReviewedAt = &t
+		req.ReviewedAt = &reviewedAt.Time
 	}
 	return req, nil
 }
@@ -130,17 +124,12 @@ func (s *Store) List(ctx context.Context, volunteerID int64) ([]Request, error)
 	var requests []Request
 	for rows.Next() {
 		var req Request
-		var startsAt, endsAt, createdAt, updatedAt string
 		var reason sql.NullString
 		var reviewedBy sql.NullInt64
-		var reviewedAt sql.NullString
-		if err := rows.Scan(&req.ID, &req.VolunteerID, &startsAt, &endsAt, &reason, &req.Status, &reviewedBy, &reviewedAt, &createdAt, &updatedAt); err != nil {
+		var reviewedAt sql.NullTime
+		if err := rows.Scan(&req.ID, &req.VolunteerID, &req.StartsAt, &req.EndsAt, &reason, &req.Status, &reviewedBy, &reviewedAt, &req.CreatedAt, &req.UpdatedAt); err != nil {
 			return nil, err
 		}
-		req.StartsAt, _ = time.Parse("2006-01-02 15:04:05", startsAt)
-		req.EndsAt, _ = time.Parse("2006-01-02 15:04:05", endsAt)
-		req.CreatedAt, _ = time.Parse("2006-01-02 15:04:05", createdAt)
-		req.UpdatedAt, _ = time.Parse("2006-01-02 15:04:05", updatedAt)
 		if reason.Valid {
 			req.Reason = reason.String
 		}
@@ -148,8 +137,7 @@ func (s *Store) List(ctx context.Context, volunteerID int64) ([]Request, error)
 			req.ReviewedBy = &reviewedBy.Int64
 		}
 		if reviewedAt.Valid {
-			t, _ := time.Parse("2006-01-02 15:04:05", reviewedAt.String)
-			req.ReviewedAt = &t
+			req.ReviewedAt = &reviewedAt.Time
 		}
 		requests = append(requests, req)
 	}