Make the project TS6 compatible

[ZheSun88]

Summary of changes

1. package.json — peerDependencies.typescript: "5" → ">=5"
2. tsconfig.build.json — added "rootDir": "src" (TS 6's TS5011 requires explicit rootDir when outDir differs from inferred root).
3. tsconfig.json — added "types": ["node"] (TS 6 no longer auto-pulls @types/node for this project, so node:crypto and the global crypto weren't found).
4. src/index.ts — replaced ambient crypto.randomUUID() with explicit import { randomUUID } from 'node:crypto'. This is the only source change; it's not a TypeScript-API change but a Node-standard-import cleanup.

Verification

• npm run build — clean.
• npm test — 12/12 pass on typescript@6.0.3.

[ZheSun88]

hey @Lodin , we are using this in hilla project which has been upgraded to use TS 6,
when build the project with it, i can see warnings/errors like

warn Could not resolve dependency:
npm warn peer typescript@"5" from tsc-template@0.2.3
npm warn node_modules/@vaadin/hilla-file-router/node_modules/tsc-template
npm warn   tsc-template@"0.2.3" from @vaadin/hilla-file-router@25.2.0-alpha5
npm warn   node_modules/@vaadin/hilla-file-router

do you have time to take a look this PR, if everything is good, make a new release?