What constitutes an act in furtherance of a person's right of petition or free speech in connection with a public issue?

An " act in furtherance of a person's right of petition or free speech under the United States or California Constitution in connection with a public issue includes: (1) any written or oral statement or writing made before a legislative, executive, or judicial proceeding, or any other official proceeding authorized by law[ and] (2) any written or oral statement or writing made in connection with an issue under consideration or review by a legislative, executive, or judicial body, or any other official proceeding authorized by law ...." ( 425.16, subd. (e)(1), (2).) " A defendant meets [his initial] burden by demonstrating that the act underlying the plaintiff's cause fits one of the[se] categories... [citation]." ( Navellier v. Sletten (2002) 29 Cal.4th 82, 88, 124 Cal.Rptr.2d 530, 52 P.3d 703.)