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.

pipeline_defs/documentary-montage.yaml

@@ -166,6 +166,7 @@ stages:
       - Resolution matches target_platform canvas
       - Uniform LUT applied across the timeline
       - Music is mixed in (MANDATORY — silent output only with explicit user opt-out recorded in brief)
+      - "render_runtime locked at proposal MUST stay 'remotion' on this pipeline until HyperFrames end-tag parity lands — the overlay/concat end-tag stack depends on Remotion CinematicRenderer components. Silent swap to hyperframes or ffmpeg is a CRITICAL governance violation."
       - "End-tag rendered via Remotion (MANDATORY — absence only with explicit opt-out). Default mode: overlay (ProRes 4444 with alpha composited on final scenes). Fallback: concat (opaque card appended after body)."
       - "Overlay mode: extract a frame from the overlay region and verify text is visible over footage, not over black. Concat mode: last frame must be the end-tag card."
       - No silent fallback from a motion-led promise