feat(registry): bring back the video-primitive moves (#3169)

Restores the 208 catalog items reverted after their previews 404'd in
production, this time on the payload mechanism rather than the .html files
that caused the outage.

The generator no longer writes a preview document to docs/public. That writer,
and the machinery under it, existed only to produce files the docs host
discards, so it is gone rather than bypassed. Items now embed the composition
itself via a payload, which is what the previous change already does for the
items that were already in the catalog.

The variables explorer is parked, not restored: it drove its preview through
the same unpublished .html path, so it would have shown an empty frame. Items
that declare variables get the live player plus the static variables table, and
reconnecting the explorer to payloads is a follow-up.

registry/components/soft-blur-in/registry-item.json

@@ -0,0 +1,82 @@
+{
+  "$schema": "https://hyperframes.heygen.com/schema/registry-item.json",
+  "name": "soft-blur-in",
+  "type": "hyperframes:component",
+  "title": "Soft Blur In",
+  "description": "A soft opacity, blur, and lift reveal for headlines, captions, and product UI callouts",
+  "tags": ["motion-primitive", "text", "reveal", "blur"],
+  "files": [
+    {
+      "path": "soft-blur-in.html",
+      "target": "compositions/components/soft-blur-in.html",
+      "type": "hyperframes:snippet"
+    }
+  ],
+  "variables": [
+    {
+      "id": "distance",
+      "type": "enum",
+      "role": "motion",
+      "label": "Distance",
+      "description": "How far the element is offset before it slides home: 14px, 28px or 52px.",
+      "default": "standard",
+      "options": [
+        {
+          "value": "close",
+          "label": "Close"
+        },
+        {
+          "value": "standard",
+          "label": "Standard"
+        },
+        {
+          "value": "far",
+          "label": "Far"
+        }
+      ]
+    },
+    {
+      "id": "direction",
+      "type": "enum",
+      "role": "motion",
+      "label": "Direction",
+      "description": "up starts the element below its resting place so it rises in, down starts it above so it drops in.",
+      "default": "up",
+      "options": [
+        {
+          "value": "up",
+          "label": "Up"
+        },
+        {
+          "value": "down",
+          "label": "Down"
+        }
+      ]
+    },
+    {
+      "id": "blur",
+      "type": "enum",
+      "role": "style",
+      "label": "Blur",
+      "description": "Starting blur radius, from a light haze to a full smear.",
+      "default": "standard",
+      "options": [
+        {
+          "value": "soft",
+          "label": "Soft"
+        },
+        {
+          "value": "standard",
+          "label": "Standard"
+        },
+        {
+          "value": "heavy",
+          "label": "Heavy"
+        }
+      ]
+    }
+  ],
+  "preview": {
+    "poster": "https://static.heygen.ai/hyperframes-oss/docs/images/catalog/components/soft-blur-in.png"
+  }
+}