hermes - 💡(How to fix) Fix web UI build: TS `baseUrl` deprecated in tsconfig.app.json breaks tsc -b (TypeScript 5.9)

Bug description

web/tsconfig.app.json uses "baseUrl": "." on line 20, which is deprecated in TypeScript 5.9 and causes tsc -b to fail during the web UI build step.

tsconfig.app.json(20,5): error TS5101: Option 'baseUrl' is deprecated and will stop functioning in TypeScript 7.0.

TypeScript 5.9 treats deprecations as errors in tsc -b mode, so the build fails before vite build ever runs.

Steps to reproduce

cd web
npm run build   # or: tsc -b

This happens regardless of NODE_ENV — it is a code incompatibility between the committed tsconfig.app.json and the TypeScript version in package.json (~5.9.3).

Expected behaviour

tsc -b succeeds and proceeds to vite build.

Actual behaviour

tsc -b exits with code 2, build fails.

Environment

• Hermes: v0.15.1
• TypeScript: 5.9.3 (from web/package.json devDependencies)
• OS: WSL2 Ubuntu 24.04 (but issue is OS-independent)

Fix

Simply remove "baseUrl": "." from web/tsconfig.app.json. With moduleResolution: "bundler", the paths configuration resolves correctly without baseUrl:

     /* Path aliases */
-    "baseUrl": ".",
     "paths": {
       "@/*": ["./src/*"]
     },

After this change, tsc -b succeeds and vite build runs to completion (verified locally).

Note: the error message suggests adding "ignoreDeprecations": "6.0" — but this does NOT work on TS 5.9 (produces TS5103: Invalid value for '--ignoreDeprecations').