Allow to set a token limit for a task

### Describe the feature or problem you'd like to solve

Currently each request consumes a certain predicable amount of premium requests - this will change soon and make it completely unpredictable, a task might accidently eat up thwo whole budget for a month.

### Proposed solution

With the upcoming https://github.blog/news-insights/company-news/github-copilot-is-moving-to-usage-based-billing/ it becomes completely unpredictable how much costs a request possibly consumes.

It would therefore be good to set a limit per session / request. If the limit is approached, copilot should ask for confirmation what to do that could be:

1. Complete as soon as possible with what was already accomplished
2. Continue with an increased budget
3. ....

### Example prompts or workflows

_No response_

### Additional context

_No response_

Nenhum arquivo, teste ou ponto de entrada é indicado. Comece localizando o tratamento de solicitações de tarefas e sessões na CLI e, em seguida, esclareça como um limite de tokens e as opções de confirmação devem funcionar. A tarefa estará concluída quando o limite for aplicado a uma solicitação ou sessão e as respostas de orçamento propostas estiverem cobertas por testes.

Escrita pelo modelo de indexação a partir do texto da issue.