[Stage 1.4] Normalize the production build and export map

[draedful]

Parent: #318

Goal

Make the @gravity-ui/graph production artifact explicit, deterministic, and suitable as the foundation for future public package extraction.

Scope

• Define one production build path for JavaScript, TypeScript declarations, styles, and required assets.
• Make the package export map explicit for @gravity-ui/graph and @gravity-ui/graph/react.
• Include @gravity-ui/graph/playwright in the explicit export map and declaration checks when it is part of the approved v2 contract.
• Preserve supported peer dependencies and keep React isolated to the React entry point.
• Remove development-only path aliases and repository-source assumptions from production output.
• Define the exact files included in the npm tarball.
• Validate package metadata and type resolution with publint and @arethetypeswrong/cli or equivalent checks.
• Verify the artifact in the isolated consumers created in Stage 1.1.

Acceptance criteria

• Every declared export resolves to an existing JavaScript and declaration artifact.
• Root and React entry points work from the packed tarball.
• The Playwright entry point works from the packed tarball when it is part of the approved v2 contract.
• A vanilla JavaScript consumer does not require React.
• Styles and other required assets have stable public paths.
• Production output contains no imports from repository source paths.
• Package metadata and type-resolution checks pass in CI.
• Storybook and E2E continue to run through public package entry points.