Adds packages/core/src/index.ts as the convenience re-export barrel for
all Dialog parts, Presence, Portal, VisuallyHidden, createFocusTrap,
createScrollLock, and createDismiss. Also resolves pre-existing biome
formatter and noNonNullAssertion violations across five files so CI passes.
Adds aria and keyboard interaction tests for the Dialog component (10 new tests, 53 total passing). Also fixes DialogContent to render with the `open` attribute so the <dialog> element is accessible in JSDOM.
Implements DialogRoot, Content, Title, Description, Trigger, Close, Portal, and Overlay parts with full context wiring, focus trap, scroll lock, and dismiss. Also fixes pre-existing TS6 exactOptionalPropertyTypes errors in create-disclosure-state and presence, and silences TS6.0 deprecation warnings via ignoreDeprecations.
Implements the controlled/uncontrolled state primitive with full TDD coverage (5 tests passing). Delegates to an internal signal when uncontrolled, defers to the external value accessor when controlled.
