refactor: remove `llm.tokens` api (#679)

examples/package.json

examples/recipes/cost-analysis.ts

packages/core/src/ChatHistory.ts

packages/core/src/GlobalsHelper.ts

packages/core/src/llm/LLM.ts

packages/core/src/llm/base.ts

packages/core/src/llm/mistral.ts

packages/core/src/llm/ollama.ts

packages/core/src/llm/types.ts

pnpm-lock.yaml