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.

tools/graphics/image_gen.py

@@ -60,6 +60,16 @@ class ImageGen(BaseTool):
         "generate_diagram_overlay",
         "generate_illustration",
     ]
+    best_for = [
+        "DEPRECATED — prefer image_selector which routes to per-provider tools "
+        "(flux_image, openai_image, recraft_image, grok_image, local_diffusion, "
+        "pexels_image, pixabay_image).",
+        "Kept only for backwards compatibility. New code should not call this.",
+    ]
+    not_good_for = [
+        "New production code — use image_selector instead.",
+        "Picking a specific provider (use the per-provider tool directly).",
+    ]
 
     input_schema = {
         "type": "object",