feat: make Create advanced settings production-aware

[faresmohamed260]

Create / Advanced settings reliability pass.

Production presets:

• FLUX.2 Klein 9B · DarkBeast V2 BFS defaults to seed 42, 4 steps, CFG 1.0
• REDGraft LTX 2.5 · Sulphur2 INT8 ConvRot defaults to seed 42, CFG 1.0 and the runtime’s fixed 11 total denoise transitions (8 base + 3 refine)
• mode changes, reference attachment, and video setting reuse restore the correct production preset instead of inheriting sampling values from another model
• original Image mode no longer exposes fake sampling/model/workflow settings while no production original-image workflow exists

LTX audit + wiring:

• current runtime does not load a separate distillation LoRA; it loads the custom REDGraft/Sulphur2 checkpoint directly
• existing custom sigma recipe is already 8 base transitions + 3 refine transitions, matching the 11-total-step two-stage distilled recipe
• video steps/CFG now travel through Create -> generation client -> Studio API -> provider form -> Modal gateway -> LTX runtime
• LTX keeps steps fixed at 11 in the UI/runtime contract rather than exposing a slider that would misrepresent the fixed custom-sigma recipe
• CFG is now live and drives both LTX CFGGuider stages; default remains 1.0
• gateway/runtime reject unsupported LTX step counts instead of silently ignoring them
• runtime health exposes total/stage step counts and explicitly reports that no separate distill LoRA is loaded

Create UI:

• video Aspect and Frame rate moved from the prompt toolbar into Advanced > Video output
• Auto aspect still follows the attached reference image; manual aspect and 24/25/30 fps behavior are preserved
• duplicate text-style Audio On/Off control removed; the circular audio button remains with accessible state/tooltips
• stock/face placeholder generations removed from Create
• Create now fills its output wall from real Favorites, automatically refreshed while Create is visible, while keeping newly generated session output ahead of favorite fallback items

Validation:

• new build-gated Create Advanced contract checks preset parity and the full LTX sampling transport
• existing FLUX worker was audited and already consumes steps/CFG in its ComfyUI workflow
• normal Studio CI and visual-regression checks are expected to validate this PR.

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Project	Deployment	Actions	Updated (UTC)
studio	Ready	Preview	Aug 25, 2026 5:56am

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