Frame: buffer cached PSF events per worker

tests/test_frame.c

@@ -222,6 +222,24 @@ int main(void) {
     goto done;
   }
   psf_kernel_cache_destroy(&loose_tail_cache);
+  /* This is the exact eligibility split that a future event sink exposes to
+   * HIP: cache event, CPU direct fallback, or min-Y discard. */
+  PsfCachedEvent prepared = {0};
+  if (psf_prepare_cached_event(&prepared, 12.25, 14.75,
+                               (LinearRgb){1.0, 1.0, 1.0}, 1.0, &psf, &cache,
+                               1.0, psf_relative_tail, 0.0) != 0 ||
+      prepared.x != 12.25 || prepared.y != 14.75 ||
+      !(prepared.support_radius > 0.0) ||
+      psf_prepare_cached_event(&prepared, 12.25, 14.75,
+                               (LinearRgb){1.0, 1.0, 1.0}, 1000.0, &psf, &cache,
+                               1.0, psf_relative_tail, 0.0) != 1 ||
+      psf_prepare_cached_event(&prepared, 12.25, 14.75,
+                               (LinearRgb){1.0, 1.0, 1.0}, 1.0, &psf, &cache,
+                               1.0, psf_relative_tail, 1.0) != 3) {
+    fputs("PSF event eligibility regression failed\n", stderr);
+    free(cached_hdr); free(reference_hdr); psf_kernel_cache_destroy(&cache);
+    goto done;
+  }
   const double phases[][2] = {{0.01, 0.99}, {0.499, 0.501}, {0.999, 0.001}};
   for (size_t phase = 0; phase < sizeof phases / sizeof *phases; ++phase) {
     memset(cached_hdr, 0, (size_t)width * height * 3 * sizeof *cached_hdr);