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/screen-demo.yaml

@@ -209,6 +209,7 @@ stages:
       - audio_enhance
     tools_available:
       - video_compose
+      - hyperframes_compose
       - audio_mixer
       - video_trimmer
       - audio_enhance
@@ -218,6 +219,8 @@ stages:
       - Output video is playable and crisp at target resolution
       - UI text remains readable after crops and scaling
       - Audio is clear with no keyboard/click noise
+      - "render_runtime in edit_decisions matches proposal_packet — silent swap is a CRITICAL governance violation"
+      - "For synthetic UI/terminal demos, render_runtime='remotion' (TerminalScene) is preferred; render_runtime='hyperframes' is valid for custom HTML UIs — in that case, lint+validate must pass before render"
     success_criteria:
       - Schema-valid render_report artifact
       - Output file exists and passes ffprobe validation