Migrate typescript config to support TS 6 and node24

[jarkkoskyt]

No description provided.

[jarkkoskyt]

Summary

Update @digabi/typescript-config and monorepo to support TypeScript 6 on Node 24.

Shared config (@digabi/typescript-config)

common-tsconfig.json

• Removed moduleResolution: "node" (removed in TS 6); each child config now sets its own strategy

root/tsconfig.json (backend/Node.js)

• module: "commonjs" → "nodenext" (CJS output preserved since packages lack "type": "module")
• target/lib: "es2022" → "es2024" + ESNext libs matching @tsconfig/node24 best practice
• Added types: ["node"] (required for @types/node globals under nodenext)
• Removed resolveJsonModule (automatic under nodenext)

public/tsconfig.json (frontend/React)

• module: "es2022" → "preserve" (pass-through for bundlers)
• Added moduleResolution: "bundler" (no .js extensions needed for frontend)
• target: "es6" → "es2020" (es6 removed in TS 6)
• lib: updated to "es2024"

Root dependency

• typescript: "^5.8.3" → "^6.0.0"

All 17 packages + template

• Added rootDir: "./src" to tsconfig.build.json (TS 6 requires explicit rootDir when outDir is set)

Source fix

• Added .js extensions to 3 dynamic import() calls in examination-utils/__tests__/examination-period.test.ts (static imports are unaffected since CJS require() supports extensionless paths)

Migration notes for consuming repos

• Backend repos extending root/tsconfig.json: upgrade to TS 6, add rootDir: "./src" to build configs, and add .js extensions to any dynamic import() calls with relative paths
• Frontend repos extending public/tsconfig.json: upgrade to TS 6, no source changes needed (bundler resolution doesn't require extensions)