fix(types): enable allowImportingTsExtensions, restore .ts on shared-types

The prior dance (93bb94a12 drop .ts, bb278fb3c switch to .js) kept
breaking one consumer or the other:

- bare specifiers (no extension) satisfied svelte-check but broke the
  Node ESM loader invoked via @tailwindcss/node during SSR — SSR of
  every (app) route 500'd with ERR_MODULE_NOT_FOUND on 'theme'.

- .js extensions satisfied svelte-check and Vite but still broke the
  Tailwind loader, because the files on disk are .ts — Node ESM walks
  the actual filesystem and can't rewrite .js → .ts the way tsc does
  at type-check time.

Flip the web app's tsconfig to "allowImportingTsExtensions": true and
put the .ts extensions back. tsc now accepts the imports, and Node's
loader finds the real file on disk. No build step, no emit, and the
shared-types package stays a pure source-only TS workspace.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/mana/apps/web/tsconfig.json

@@ -10,6 +10,7 @@
 		"sourceMap": true,
 		"strict": true,
 		"moduleResolution": "bundler",
+		"allowImportingTsExtensions": true,
 		"verbatimModuleSyntax": true
 	}
 }