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the same unpublished .html path, so it would have shown an empty frame.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

@@ -0,0 +1,72 @@
+{
+  "$schema": "https://hyperframes.heygen.com/schema/registry-item.json",
+  "name": "morph-swap",
+  "type": "hyperframes:component",
+  "title": "Morph Swap",
+  "description": "Two slotted siblings stacked at one shared center: A holds, then condenses or reshapes into B on a shared 50% 50% transform origin. Condense shrink-fades A exactly as B scales up; reshape morphs the silhouette on scaleX/scaleY, never width or height tweens. Token card defaults render when a slot is left empty.",
+  "tags": ["transition", "morph", "swap", "condense", "reshape", "holdable", "slots"],
+  "jobs": ["bridge"],
+  "family": "transitions",
+  "profile": "holdable",
+  "evidence": "Wave J2-4: flagship close condense morph (07-close) and problem reshape morph (02-problem) generalized onto content slots",
+  "syncPoints": [{ "id": "morph-land", "phase": "in", "offset": 2.15 }],
+  "files": [
+    {
+      "path": "morph-swap.html",
+      "target": "compositions/components/morph-swap.html",
+      "type": "hyperframes:snippet"
+    }
+  ],
+  "variables": [
+    {
+      "id": "swap_at",
+      "type": "number",
+      "role": "timing",
+      "label": "Swap start",
+      "description": "Seconds after mount start when the morph begins.",
+      "default": 1.4,
+      "min": 0.1,
+      "max": 8,
+      "step": 0.05,
+      "unit": "s"
+    },
+    {
+      "id": "register",
+      "type": "enum",
+      "role": "style",
+      "label": "Register",
+      "description": "Morph mechanic: condense shrink-fades A into B at center; reshape morphs the silhouette on scaleX/scaleY.",
+      "default": "condense",
+      "options": [
+        { "value": "condense", "label": "Condense" },
+        { "value": "reshape", "label": "Reshape" }
+      ]
+    },
+    {
+      "id": "accent",
+      "type": "enum",
+      "role": "style",
+      "label": "Accent",
+      "description": "Incoming card accent color.",
+      "default": "green",
+      "options": [
+        { "value": "green", "label": "Green" },
+        { "value": "blue", "label": "Blue" },
+        { "value": "violet", "label": "Violet" }
+      ]
+    },
+    {
+      "id": "exit",
+      "type": "enum",
+      "role": "timing",
+      "label": "Exit",
+      "description": "Outgoing transition. None holds the final frame.",
+      "default": "none",
+      "options": [
+        { "value": "none", "label": "None" },
+        { "value": "fade", "label": "Fade" },
+        { "value": "up", "label": "Up" }
+      ]
+    }
+  ]
+}