## PR Description
- Uses `expr-eval` to enable front components (SDK plugins) to define
conditional availability as declarative expressions.
- Moves shared types and constants to `twenty-shared`
- Introduces a `conditionalAvailabilityExpression` field on
`CommandMenuItemEntity`, allowing command menu items to store an
`expr-eval` compatible expression string that is evaluated against a
CommandMenuContext to determine if the item should be shown.
- Creates an esbuild transform plugin
`conditional-availability-transform-plugin` in `twenty-sdk` that
converts TypeScript conditional availability expressions into
`expr-eval` compatible syntax at build time, so SDK developers can write
natural TS expressions that get transformed to evaluable strings.
- Removes deprecated `forceRegisteredActionsByKey` state and its usage.
- Creates `useCommandMenuContext` hook that builds the full
`CommandMenuContext` object from React state, which is then passed to
`useCommandMenuItemFrontComponentActions` for evaluating conditional
availability expressions.
