feat: generative card grammar, new motion system and trending suggestions

[nikolmedo]

• Add an enum-only card grammar to the Scene contract (surface, corner, header, pattern, size, per-kind variant, typeScale), mirrored and drift-checked on server and client, with per-kind renderer variants and a 12-column module grid driven by a single --cols source.
• Seed a deterministic client fallback for modules the model leaves plain, and seed SVG card patterns from the module's scene index.
• Wire mood and density into CSS, drop the anti-variety prompt rules and raise the answer temperature to 0.6.
• Replace blur entrances with five clip-path/transform families, make reveal "count" drive a decoding count-up, cap the cascade, fix the holding window, crossfade the skeleton and FLIP span changes.
• Pause and slim the ambient canvas and stop per-frame React renders in the count-up.
• Generate landing suggestions from Google Trends through the fast model, with validated output, a TTL cache, single-flight and a failure cooldown, falling back to the static examples.