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the same unpublished .html path, so it would have shown an empty frame.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/slot-machine-roll/slot-machine-roll.html

@@ -0,0 +1,136 @@
+<!--
+  Slot Machine Roll - remocn typography primitive for HyperFrames.
+
+  Paste the markup, CSS and script into a composition. Drive the timeline
+  integration from a paused GSAP timeline so renders remain deterministic.
+
+  Variables. The script reads each one, falls back to the declared default on
+  anything missing or unrecognised, and writes the result as a custom property
+  the CSS below consumes. The timeline recipe stays untouched by them: it keeps
+  driving one vertical offset of exactly one row, and these decide how tall that
+  row is, which way it travels and what it lands on.
+
+    - result (text, default "A7K"): the characters the reels land on, one reel
+      column per character. Whitespace is stripped, and blank or non-text input
+      falls back to the default three. Every reel starts on a zero.
+    - direction (up | down, default up): which way the reels roll. up lifts the
+      zero out through the top, down drops it out through the bottom.
+    - size (small | standard | large, default standard): reel height and type
+      size, 48px, 74px or 104px. The roll distance is scaled by the same factor,
+      so whatever the size the reel still lands exactly one row on.
+    - tone (ink | paper | accent, default ink): character colour. ink is
+      near-black for light frames, paper near-white for dark ones, accent rides
+      --brand.
+
+  On every default the result is identical to the original: three 74px reels in
+  near-black rolling 0 up to A, 7 and K.
+-->
+
+<div
+  class="hf-remocn-slot-machine-roll"
+  data-composition-variables='[
+    { "id": "result", "type": "string", "role": "content", "label": "Result", "description": "Characters the reels land on, one reel column per character. Whitespace is stripped and every reel starts on a zero.", "default": "A7K" },
+    { "id": "direction", "type": "enum", "role": "motion", "label": "Direction", "description": "Which way the reels roll: up lifts the zero out through the top, down drops it out through the bottom.", "default": "up", "options": [{ "value": "up", "label": "Up" }, { "value": "down", "label": "Down" }] },
+    { "id": "size", "type": "enum", "role": "layout", "label": "Size", "description": "Reel height and type size. The roll distance scales with it so the reel always lands exactly one row on.", "default": "standard", "options": [{ "value": "small", "label": "Small" }, { "value": "standard", "label": "Standard" }, { "value": "large", "label": "Large" }] },
+    { "id": "tone", "type": "enum", "role": "style", "label": "Tone", "description": "Character colour: ink for light frames, paper for dark ones, accent rides --brand.", "default": "ink", "options": [{ "value": "ink", "label": "Ink" }, { "value": "paper", "label": "Paper" }, { "value": "accent", "label": "Accent" }] }
+  ]'
+>
+  <span
+    ><i>0<br />A</i></span
+  ><span
+    ><i>0<br />7</i></span
+  ><span
+    ><i>0<br />K</i></span
+  >
+</div>
+
+<style>
+  .hf-remocn-slot-machine-roll {
+    color: var(--hf-slot-color, #18181b);
+    font-family: Inter, system-ui, sans-serif;
+    font-weight: 900;
+    letter-spacing: -0.04em;
+  }
+  .hf-remocn-slot-machine-roll {
+    display: inline-flex;
+    gap: 6px;
+    height: var(--hf-slot-row, 74px);
+    overflow: hidden;
+    font:
+      900 var(--hf-slot-row, 74px)/1 ui-monospace,
+      SFMono-Regular,
+      Menlo,
+      monospace;
+  }
+  .hf-remocn-slot-machine-roll span {
+    display: block;
+    height: var(--hf-slot-row, 74px);
+    overflow: hidden;
+  }
+  .hf-remocn-slot-machine-roll i {
+    display: block;
+    font-style: normal;
+    transform: translateY(
+      calc(
+        var(--hf-slot-base, 0px) + var(--hf-slot-y, 0px) * var(--hf-slot-dir, 1) *
+          var(--hf-slot-gain, 1)
+      )
+    );
+  }
+</style>
+
+<script>
+  (function () {
+    "use strict";
+
+    var vars =
+      window.__hyperframes && window.__hyperframes.getVariables
+        ? window.__hyperframes.getVariables()
+        : {};
+
+    // Unrecognised overrides return to their declared defaults.
+    function pick(table, value, fallback) {
+      return Object.prototype.hasOwnProperty.call(table, value) ? value : fallback;
+    }
+
+    var directions = { up: 1, down: -1 };
+    var sizes = { small: 48, standard: 74, large: 104 };
+    var tones = {
+      ink: "#18181b",
+      paper: "#fafafa",
+      accent: "var(--brand, #34d399)",
+    };
+
+    var dir = directions[pick(directions, vars.direction, "up")];
+    var row = sizes[pick(sizes, vars.size, "standard")];
+    var tone = tones[pick(tones, vars.tone, "ink")];
+    var result = (typeof vars.result === "string" ? vars.result : "").replace(/\s+/g, "");
+    if (result.length === 0) result = "A7K";
+
+    var roots = document.querySelectorAll(".hf-remocn-slot-machine-roll");
+    for (var i = 0; i < roots.length; i += 1) {
+      var root = roots[i];
+      root.style.setProperty("--hf-slot-row", row + "px");
+      root.style.setProperty("--hf-slot-gain", String(row / 74));
+      root.style.setProperty("--hf-slot-dir", String(dir));
+      // Rolling down starts one row up, so the zero still sits in frame at rest.
+      root.style.setProperty("--hf-slot-base", (dir === 1 ? 0 : -row) + "px");
+      root.style.setProperty("--hf-slot-color", tone);
+      root.textContent = "";
+      for (var j = 0; j < result.length; j += 1) {
+        var reel = document.createElement("i");
+        reel.appendChild(document.createTextNode(dir === 1 ? "0" : result.charAt(j)));
+        reel.appendChild(document.createElement("br"));
+        reel.appendChild(document.createTextNode(dir === 1 ? result.charAt(j) : "0"));
+        var slot = document.createElement("span");
+        slot.appendChild(reel);
+        root.appendChild(slot);
+      }
+    }
+  })();
+</script>
+
+<!--
+  Timeline integration:
+  tl.fromTo('.hf-remocn-slot-machine-roll i', { '--hf-slot-y': '0px' }, { '--hf-slot-y': '-74px', duration: 0.52, stagger: 0.06, ease: 'power3.inOut' }, startTime);
+-->