ADR-0050 implementation: finish layout-forwarding (DrawerForm + entries) + narrow FormView.type (breaking)

[os-zhuang]

Tracks the remaining ADR-0050 (form layout ⊥ presentation) implementation after the additive first step landed.

Done (additive, non-breaking):

• Full-page record form honours layout — fix(form): honour form view layout (tabbed/wizard/split) in full-page record form (framework#1890) #1762.
• Modal forms can host a tabbed layout — feat(form): modal forms can host a tabbed layout — modal+tabbed (framework#1890) #1764 (ModalForm.contentLayout + AppContent forwarding; browser-verified modal+tabbed).

Remaining A (additive, non-breaking) — consistency:

• DrawerForm: add contentLayout (tabbed) like ModalForm.
• Forward layout from the other modal entry points: useActionModal, DashboardView (and any list addRecord modal path) so every container honours the form view's layout.

Remaining B (BREAKING, spec-major — needs architect sign-off, ADR-0050):

• Narrow FormViewSchema.type to layout-only (simple/tabbed/wizard); drop drawer/modal (caller-supplied containers) and split (covered by subforms + list split-detail).
• ObjectForm: remove the retired drawer/modal/split branches.
• Migrate the 5 demo named views (showcase task split/quick; hotcrm lead split/drawer/modal) to layout demos + open-mode demos.
• spec-major changeset + downstream (hotcrm/templates) coordination. Bundle into the next spec-major batch rather than a standalone major bump.

See ADR-0050 (docs/adr/0050-form-layout-vs-presentation.md). Refs #1890.