Address follow-up review: cheaper avatars, list limits, less chatter.

Switch avatar resize to ApproxBiLinear, cap hunt/profile/admin list queries, drop redundant admin/profile lookups, dedupe CI on app PRs, and refresh stale todo.md notes.

internal/store/user.go

@@ -172,7 +172,7 @@ func CountAdmins(ctx context.Context, db *sql.DB) (int, error) {
 }
 
 func ListUsers(ctx context.Context, db *sql.DB) ([]User, error) {
-	rows, err := sqlc.New(db).ListUsers(ctx)
+	rows, err := sqlc.New(db).ListUsers(ctx, AdminUsersLimit)
 	if err != nil {
 		return nil, err
 	}