Every flourish gets its own file, and a workshop to watch them in

The effects move out of Board.svelte into src/fx-sprites/ — one
component per flourish, markup and animation CSS together, so editing
the fireball means opening Fireball.svelte and nothing else. A
registry (index.ts) maps kind to sprite; Board renders through it.
The event mapping stays in fx.ts.

And a viewer: /?fx opens the Flourish Workshop — every sprite on a
labeled parchment tile, replaying on a 2.2-second beat. Under the dev
server, editing any sprite file hot-reloads the gallery mid-loop.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packages/web/src/fx-sprites/Burst.svelte

@@ -0,0 +1,26 @@
+<script lang="ts">
+  import type { FxOf } from "../fx";
+  import { center } from "./geom";
+  let { fx }: { fx: FxOf<"burst"> } = $props();
+  const c = $derived(center(fx.at));
+</script>
+
+<circle cx={c.x} cy={c.y} r="4" class="burst" />
+<circle cx={c.x} cy={c.y} r="4" class="burst late" />
+
+<style>
+  .burst {
+    transform-box: fill-box;
+    transform-origin: center;
+    fill: none;
+    stroke: #ff8c1a;
+    stroke-width: 4;
+    animation: ring 0.5s ease-out 0.05s forwards;
+    opacity: 0;
+  }
+  .burst.late { stroke: #ffd27a; animation-delay: 0.16s; }
+  @keyframes ring {
+    0% { opacity: 0.95; transform: scale(1); }
+    100% { opacity: 0; transform: scale(5); }
+  }
+</style>