Three related fixes touching the menu surface:
1. **Remove `modal` from DropdownMenu** (#127). The prop was declared in
soma but never wired to anything — no overlay, no pointer-events
blocker, no scrim. ark-ui / Headless-UI / Chakra all treat menu as
non-modal by convention; Dialog/Drawer/AlertDialog cover blocking
semantics. Drop it from soma (types, provider opts, component, test
fixture), the eidos doc comment, the menubar consumer, and the
dropdown-menu demo (state, control, snippet, API table, parity table).
2. **DropdownMenu.Trigger now renders `<Button>` internally** (#120
first consumer). Default variant='surface', size='md', intent='neutral'.
`variant` is narrowed to ControlVariant (`'surface' | 'outline' | 'ghost'`)
per DEMO_AUTHORING_GUIDE §12.7 so the trigger stays consistent with
the form-control surface (Field/Select/Combobox) instead of inheriting
Button's wider 6-variant set. The eidos demo exposes variant/size/intent
chips that match the canonical narrowed vocab (Intent: neutral · affirm
· fulfill · risk · threat · loss). Trigger's per-recipe CSS dropped —
chrome comes from button.css.
3. **Menu-item unchecked indicators** (follow-up to #118). CheckboxItem
and RadioItem now paint an empty outlined box / circle even when
unchecked, so the user can tell at a glance which rows are checkable.
Checked state fills with the accent color via the same `::before`. The
reserved padding slot (26px) keeps row text from shifting when state
flips.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>