star wipe!

here is my/gemini's attempt

```css

@keyframes star-shrink {
from {
clip-path: polygon(
50% -125%,
/* P1 */ 88.5% -2.5%,
/* P2 */ 218% -2.5%,
/* P3 */ 113% 74.5%,
/* P4 */ 151.5% 193.5%,
/* P5 */ 50% 120%,
/* P6 */ -51.5% 193.5%,
/* P7 */ -13% 74.5%,
/* P8 */ -118% -2.5%,
/* P9 */ 11.5% -2.5% /* P10 */
);
}
to {
clip-path: polygon(
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord)
);
}
}

::view-transition-old(star-in) {
animation: none;
animation-name: star-shrink;
animation-duration: 0.7s;
animation-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
animation-fill-mode: forwards;
z-index: 1;
}

::view-transition-new(star-in) {
animation: none;
z-index: 0;
}

::view-transition-group(root),
::view-transition-image-pair(root) {
animation: none;
mix-blend-mode: normal;
}

@keyframes star-expand {
from {
clip-path: polygon(
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord),
var(--transition-coord)
);
}
to {
clip-path: polygon(
50% -125%,
/* P1 */ 88.5% -2.5%,
/* P2 */ 218% -2.5%,
/* P3 */ 113% 74.5%,
/* P4 */ 151.5% 193.5%,
/* P5 */ 50% 120%,
/* P6 */ -51.5% 193.5%,
/* P7 */ -13% 74.5%,
/* P8 */ -118% -2.5%,
/* P9 */ 11.5% -2.5% /* P10 */
);
}
}

@keyframes fade-out {
to {
opacity: 0;
}
}

::view-transition-new(star-out) {
animation: none;
animation-name: star-expand;
animation-duration: 0.7s;
animation-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
animation-fill-mode: both;
z-index: 1;
}

/* Apply a fade-out animation to the OLD content snapshot FOR 'star-out' */
::view-transition-old(star-out) {
animation: none;
animation-name: fade-out;
animation-duration: 0.7s;
animation-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
animation-fill-mode: both;
z-index: 0;
}
```

https://www.youtube.com/watch?v=72bUheqRE5o

Start by reviewing the proposed CSS in the issue and the linked demonstration video to understand the intended star-wipe behavior. Identify where this transition belongs in the transition.css project, then verify that the finished change reproduces the demonstrated wipe without breaking the existing transitions.

Written by the indexing model from the issue text.