Add optional TypeScript support

[DavidMStraub]

No description provided.

[Copilot]

Pull request overview

This PR adds optional TypeScript support to the Gramps Web frontend, allowing new files to be written in .ts while existing .js files remain untouched. The infrastructure changes span the build pipeline (Rollup), the dev server (esbuild), linting/formatting configuration, CI, and developer documentation.

Changes:

• Adds @rollup/plugin-typescript for production builds and @web/dev-server-esbuild for dev server TypeScript transpilation, along with typescript, @typescript-eslint/parser, and a new tsconfig.json
• Updates ESLint, Prettier, and lint-staged configurations to process both .js and .ts files
• Adds a typecheck npm script (tsc --noEmit) and a corresponding CI step, and documents the TypeScript workflow in CLAUDE.md

Reviewed changes

Copilot reviewed 5 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tsconfig.json	New TypeScript configuration with Lit decorator support, noEmit, and strict mode
rollup.config.js	Adds @rollup/plugin-typescript to the Rollup plugin chain for production builds
web-dev-server.config.mjs	Adds esbuildPlugin for TypeScript transpilation during development
package.json	Adds TS-related devDependencies, updates lint/format scripts for .ts files, adds typecheck script, adds ESLint override for .ts files
package-lock.json	Lock file updates for new dependencies
CLAUDE.md	Documents TypeScript conventions, tooling, and Lit decorator usage
.github/workflows/test.yml	Adds npm run typecheck step to CI pipeline

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.