feat(registry): seed blocks — data-chart, flowchart, logo-outro (#259)

Extract three standalone blocks from existing example templates:

- data-chart: Animated bar + line chart with staggered reveal (from nyt-graph)
- flowchart: Decision tree with SVG connectors and cursor interaction (from decision-tree)
- logo-outro: Cinematic logo reveal with tagline and URL pill (from product-promo)

Each block is a complete HTML composition installable via `hyperframes add <name>`.
Blocks render as iframes in host compositions.

registry/registry.json

@@ -34,6 +34,18 @@
     {
       "name": "nyt-graph",
       "type": "hyperframes:example"
+    },
+    {
+      "name": "data-chart",
+      "type": "hyperframes:block"
+    },
+    {
+      "name": "flowchart",
+      "type": "hyperframes:block"
+    },
+    {
+      "name": "logo-outro",
+      "type": "hyperframes:block"
     }
   ]
 }