hyperframes: add HTML/CSS/GSAP as a parallel composition runtime

Separates creative grammar (renderer_family) from technical engine
(render_runtime) so HyperFrames can stand alongside Remotion as a
first-class runtime instead of masquerading as a Remotion sub-case.
Locks runtime choice at proposal stage and enforces it end-to-end: the
schemas require it, video_compose routes by it, the reviewer fails
closed on silent swaps, and a parametrized contract test walks every
pipeline manifest to ensure each planning-stage skill explains the
conversation to the user. Adds hyperframes_compose (scaffold/lint/
validate/render/doctor/add_block), a playbook -> CSS style bridge, and
vendored HyperFrames Layer 3 skills from commit d291358, pinned via
PROVENANCE.md for future re-sync. Final_review now records
render_runtime_used and runtime_swap_detected so compose lies are
catchable after the fact.

render_demo.py

@@ -1,3 +1,15 @@
+"""Render the curated zero-key Remotion demos.
+
+This script is Remotion-specific by design — the demos live in
+`remotion-composer/public/demo-props/` as JSON props for existing React
+scene components. It is NOT a cross-runtime demo harness.
+
+For a HyperFrames demo, run `make hyperframes-doctor` to verify the runtime
+floor, then either scaffold a real composition via `npx hyperframes init`
+or drive `hyperframes_compose` from the Agent SDK. HyperFrames demos are
+authored as HTML + GSAP in a project workspace, not as JSON props here.
+"""
+
 from __future__ import annotations
 
 import argparse