build: Update TypeScript to 5.9

[frankieyan]

Short description

As titled. This is a pre-requisite to updating Ariakit.

Reference: ariakit/ariakit#3733

We also have to update to the last 6.x version of Storybook for compatibiltiy with TypeScript 5.0: storybookjs/storybook#21745

Test plan

• Quick smoke test in Storybook

[Copilot]

Pull Request Overview

This PR refactors import statements across the codebase to separate type imports from value imports using TypeScript's import type syntax, and updates several package versions including TypeScript (4.8.3 → 5.9.3), @storybook/react (^6.5.3 → 6.5.17-alpha.0), and @doist/tsconfig (^1.0.0 → 2.0.0).

Key changes:

• Systematically separates type imports from value imports using import type syntax
• Updates TypeScript to version 5.9.3
• Updates Storybook React to alpha version 6.5.17-alpha.0
• Adds fork-ts-checker-webpack-plugin 6.5.3 as an explicit dependency

Reviewed Changes

Copilot reviewed 27 out of 28 changed files in this pull request and generated 1 comment.

File	Description
package.json	Updates TypeScript to 5.9.3, Storybook to 6.5.17-alpha.0, adds fork-ts-checker-webpack-plugin, updates @doist/tsconfig to 2.0.0
package-lock.json	Reflects package.json dependency updates with resolved versions
src//*.tsx, src//*.ts	Separates type imports using import type syntax across all TypeScript/TSX files

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