In-app editor P3 — unify authoring polish (state/mood deltas in shared controls)

[mabry1985]

Bring the two editors to feature parity both ways (plan: docs/internal/inapp-editor-parity.md).

• Port the in-app state/mood delta authoring (FieldDeltaSlider / AuthoringContext) into the shared controls so BOTH editors have it.
• Preview parity (voice-state + mood simulation).
• Open: 'fork a built-in variant into an editable .orbis' so users can start from a built-in look.

Depends on P1 + P2.

[mabry1985]

Deferred along with #547 — see #554 (routing to the marketing editor for now).