chore: Add void to mark bootstrap Promise as intentionally not awaited

[minhtc-tech]

• The npm run lint returns a warning about the bootstrap function inside main.ts.
• Since this function is being used at the top level of a CommonJS module, we cannot use await here.
• We should fix it by adding the keyword void to mark the Promise bootstrap function as intentionally not awaited.
• References: https://typescript-eslint.io/rules/no-floating-promises/#ignorevoid