chore: convert repository to ESM

[Mrtenz]

Currently, the package is built as both CommonJS and ESM using @ts-bridge/cli. This PR replaces that with ESM-only output built with standard tsc.

The motivation is to simplify the build toolchain by removing thets-bridge dependency in preparation for the TypeScript 6+ upgrade.

Examples

Based on MetaMask/core#9536.

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Note

Medium Risk
Publishing moves to ESM-only entrypoints, which can break CommonJS require() consumers; build and test tooling changes also alter how releases are validated compared to the prior dual-format + attw flow.

Overview
This PR makes the module template ESM-only and simplifies how it is built and published.

Package surface: Adds "type": "module" and collapses exports to a single ./dist/index.js plus ./dist/index.d.ts, dropping separate main/module and conditional import/require entries. Yarn workspace constraints in yarn.config.cjs are updated to enforce that shape.

Build & test: Replaces @ts-bridge/cli with tsc via tsconfig.build.json (JS emit enabled, not declarations-only). Removes @arethetypeswrong/cli, ts-node, and the test:package / attw pack check; test is now Vitest only. Test imports use explicit ./index.js paths for Node16 resolution.

Tooling: ESLint turns off import-x/no-useless-path-segments for ESM. LavaMoat Yarn plugins point at .cjs files, build gets a new lavamoat/scripts.build.json permission profile, and scriptsConfig wires build/test to the appropriate LavaMoat configs.

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