[ci] Add Wan2.2-TI2V-5B SSIM regression test (#1772)

Co-authored-by: SuhaanCommits <suhaan@cedar.build>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: SolitaryThinker <wlsaidhi@gmail.com>

.github/scripts/plan_merge_ci.py

@@ -222,6 +222,7 @@ FAMILY_COVERAGE = (
             "test_causal_similarity.py",
             "test_wan_i2v_similarity.py",
             "test_wan_t2v_similarity.py",
+            "test_wan_ti2v_similarity.py",
         ),
     ),
     FamilyCoverage(