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the same unpublished .html path, so it would have shown an empty frame.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/offset-path-traveler/registry-item.json

@@ -0,0 +1,51 @@
+{
+  "$schema": "https://hyperframes.heygen.com/schema/registry-item.json",
+  "name": "offset-path-traveler",
+  "type": "hyperframes:component",
+  "title": "Offset Path Traveler",
+  "description": "A slotted traveler follows an authored path with tangent rotation, curved entry, and curved exit.",
+  "tags": ["motion-primitive", "product-demo", "path", "traveler", "auto-rotate"],
+  "jobs": ["demonstrate"],
+  "family": "product-demo",
+  "profile": "path-travel",
+  "evidence": "Wave I I6 approved contract: authored path travel with tangent auto-rotation and arc-law entry and exit",
+  "syncPoints": [{ "id": "path-arrive", "phase": "in", "offset": 1.2 }],
+  "files": [
+    {
+      "path": "offset-path-traveler.html",
+      "target": "compositions/components/offset-path-traveler.html",
+      "type": "hyperframes:snippet"
+    }
+  ],
+  "variables": [
+    {
+      "id": "path",
+      "type": "string",
+      "role": "content",
+      "label": "Path",
+      "description": "SVG path data authored in a 1000 by 500 route viewBox.",
+      "default": "M -90 390 C 150 490 190 70 430 185 C 650 300 720 105 850 145 C 970 180 1030 85 1090 35"
+    },
+    {
+      "id": "traveler_label",
+      "type": "string",
+      "role": "content",
+      "label": "Traveler label",
+      "description": "Text displayed inside the default traveler chip.",
+      "default": "Live preview"
+    },
+    {
+      "id": "accent",
+      "type": "enum",
+      "role": "style",
+      "label": "Accent",
+      "description": "Color used by the traveler and route.",
+      "default": "green",
+      "options": [
+        { "value": "green", "label": "Green" },
+        { "value": "blue", "label": "Blue" },
+        { "value": "violet", "label": "Violet" }
+      ]
+    }
+  ]
+}