fix: Preserve baseUrl when writing paths in library tsconfig update

[Copilot]

TypeScript requires baseUrl to be set whenever paths mappings are used — without it, path aliases are silently ignored. The updateTsConfig function was deleting baseUrl while still writing paths, producing an invalid config.

Changes

• library.factory.ts: Replace delete tsconfig.compilerOptions.baseUrl with tsconfig.compilerOptions.baseUrl = './' to ensure paths mappings are valid
• library.factory.test.ts: Update affected test assertions to expect baseUrl: "./" rather than undefined

Before:

{
  "compilerOptions": {
    "paths": {
      "app/my-lib": ["./libs/my-lib/src"],
      "app/my-lib/*": ["./libs/my-lib/src/*"]
    }
  }
}

After:

{
  "compilerOptions": {
    "baseUrl": "./",
    "paths": {
      "app/my-lib": ["./libs/my-lib/src"],
      "app/my-lib/*": ["./libs/my-lib/src/*"]
    }
  }
}

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