feat(seo): add sitemap generator

internal/repository/user_repo.go

@@ -379,6 +379,27 @@ func (r *UserRepo) Search(ctx context.Context, q string, limit, offset int) ([]m
 	return out, total, rows.Err()
 }
 
+// AllHandles returns every user's handle, for the public-profile sitemap.
+// Projection-only (handle is unique + indexed), cheap to sweep. Excludes the
+// reserved "me" handle (the signed-in user's own private library route).
+func (r *UserRepo) AllHandles(ctx context.Context) ([]string, error) {
+	rows, err := r.pg.Pool.Query(ctx,
+		`SELECT handle FROM users WHERE handle <> '' AND handle::text <> 'me' ORDER BY handle`)
+	if err != nil {
+		return nil, fmt.Errorf("list handles: %w", err)
+	}
+	defer rows.Close()
+	handles := []string{}
+	for rows.Next() {
+		var h string
+		if err := rows.Scan(&h); err != nil {
+			return nil, fmt.Errorf("scan handle: %w", err)
+		}
+		handles = append(handles, h)
+	}
+	return handles, rows.Err()
+}
+
 // RecentlyJoined returns up to `limit` users who registered on/after `since`,
 // newest first, as a discovery list for the feed's "new on the platform"
 // strip. Excludes the viewer, anyone the viewer already has a follow edge with