feat(registry): add 15 caption style catalog components

Add 15 caption overlay components to the registry, covering a wide
range of animation techniques:

Standalone origins (6):
- caption-pill-karaoke: pill container + karaoke word highlight
- caption-neon-accent: multi-color neon glow with wiggle drift
- caption-weight-shift: font-weight transition between lines
- caption-emoji-pop: emoji + stroked text + horizontal squeeze
- caption-editorial-emphasis: dual-font (Inter + Playfair) emphasis
- caption-parallax-layers: 3D text layering with vertical stretch

Gallery picks (9):
- caption-glitch-rgb: RGB chromatic aberration + CRT scanlines
- caption-typewriter: green terminal char-by-char with cursor
- caption-matrix-decode: scramble-reveal character animation
- caption-particle-burst: keyword particle explosions
- caption-texture-lava: flowing lava texture mask
- caption-clip-wipe: clip-path left-to-right wipe reveal
- caption-kinetic-slam: full-screen single-word slam
- caption-gradient-fill: gradient-clipped text + elastic bounce
- caption-neon-glow: cyan/magenta neon glow accents

Each component includes the reusable HTML, a demo composition,
and registry-item.json. All use a generic HyperFrames transcript.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

registry/components/caption-gradient-fill/registry-item.json

@@ -0,0 +1,15 @@
+{
+  "$schema": "https://hyperframes.heygen.com/schema/registry-item.json",
+  "name": "caption-gradient-fill",
+  "type": "hyperframes:component",
+  "title": "Gradient Fill",
+  "description": "Gradient-clipped text with elastic bounce entrance",
+  "tags": ["captions", "caption-style", "gradient", "colorful"],
+  "files": [
+    {
+      "path": "caption-gradient-fill.html",
+      "target": "compositions/components/caption-gradient-fill.html",
+      "type": "hyperframes:snippet"
+    }
+  ]
+}