chore(tsconfig): drop baseUrl so the config survives TypeScript 7 - #7193

TypeScript 6 reports this as an error:

Option 'baseUrl' is deprecated and will stop functioning in TypeScript 7.0.
  Specify compilerOption '"ignoreDeprecations": "6.0"' to silence this error.

The repo pins [email protected], so npm run typecheck is quiet today. An editor running a newer TypeScript flags it now, and it becomes a hard failure the moment the pin moves to 7.

Why removing it rather than silencing it

baseUrl here only anchors paths, and paths has not needed it since TypeScript 4.4 — entries resolve relative to the tsconfig that declares them. That makes "src/*" → "./src/*" the only other change.

"ignoreDeprecations": "6.0" would also make the message go away, but it buys one major version and has to be revisited. This makes the config correct instead.

Why it is safe

baseUrl has a second effect — it lets bare specifiers resolve against the base directory — so removing it can break imports that quietly relied on that. Checked: there are no from "src/…"-style imports anywhere under src/, only relative ones and the @/ alias.

Build and tests never read this setting at all. Both vite.config.ts and vitest.config.ts declare the alias themselves:

resolve: { alias: { "@": path.resolve(__dirname, "./src") } }

so the change is type-level only.

Verification

• tsc --noEmit: 0 errors before, 0 after, with @/ imports in 250 files under src/ still resolving — if the alias had broken, that would be hundreds of Cannot find module errors, not silence.
• Re-ran the same config under TypeScript 6.0.3: the deprecation is gone, and no new diagnostic replaces it.