chore(repo): upgrade TypeScript to 6.0

Three TS 6 defaults/deprecations land on this repo; all handled:

- tsup's dts worker injects baseUrl into the loaded tsconfig, which
  TS 6 rejects with TS5101 — the exact breakage that motivated the
  ^5.9.3 workspace pin. Waived via ignoreDeprecations: "6.0" in
  tsconfig.base.json (baseUrl still functions across 6.x; the waiver
  dies with tsup-based dts generation before TS 7).
- noUncheckedSideEffectImports (now default) rejects the story files'
  stylesheet imports — added a '*.css' ambient next to the existing
  '*.scss' shim.
- The workspace pin stays, retargeted at ^6.0.3: TS 7 ships without
  the programmatic JS API (7.1) that typescript-eslint and tsup both
  require, so autoInstallPeers must not resolve it.

typescript-eslint 8.x supports TS <6.1.0; full preflight green.

Author: AIEPhoenix

package.json

@@ -64,7 +64,7 @@
     "sass": "^1.101.0",
     "storybook": "^10.4.6",
     "tsup": "^8.5.1",
-    "typescript": "^5.9.3",
+    "typescript": "^6.0.3",
     "typescript-eslint": "^8.58.2",
     "vitest": "^4.1.10"
   }

packages/mantine/src/typings/shims.d.ts

@@ -1,6 +1,10 @@
 /**
- * Ambient declaration for style imports. The styles are compiled and bundled
- * by the tsup build (esbuild-sass-plugin); for `tsc --noEmit` the import only
- * needs to resolve.
+ * Ambient declarations for style imports. The styles are compiled and bundled
+ * by the tsup build (esbuild-sass-plugin) or served by vite (storybook); for
+ * `tsc --noEmit` the import only needs to resolve. `*.css` exists for the
+ * storybook program (tsconfig.storybook.json includes this typings dir):
+ * TypeScript 6's `noUncheckedSideEffectImports` default rejects side-effect
+ * imports it cannot resolve, and story files import stylesheet packages.
  */
 declare module '*.scss';
+declare module '*.css';